School stage of the All-Russian Olympiad for schoolchildren in physics (Grade 7).

Agreed I approve:

At the methodological council "IMC" Director of MBOU DPO "IMC" "_____" __________ 2014_____ ______________

Protocol No. ____ "______" ______________ 2014

"_____" __________ 2014_____

Tasks

school stage of the All-Russian Olympiad

students in physics

7-11 grades

· the duration of the tasks is 120 minutes.

· Participants of the Olympiad are prohibited from bringing their notebooks, reference new literature and textbooks, electronic equipment (except calculators).

· The school stage of the Physics Olympiad is held in one round of individual competitions of participants. Participants submit a report on the work done in writing. Complement verbal questioning is not allowed

· To complete the tasks of the Olympiad, each participant is given a notebook in a cage

· Participants of the Olympiad are prohibited from using a pen with red or green ink to write down solutions. During the rounds, the participants of the Olympiad are prohibited from usinguse any means of communication

· 15 minutes after the start of the round, the participants of the Olympiad can ask questions onthe terms of the tasks (in writing). In this regard, audience attendants should havesheets of paper for questions. Substantive questions are answeredjury members for all participants of this parallel. Incorrect questions or questions indicating that the participant did not read the condition carefully should be answered "no comments".

· Audience attendant reminds participants of the time left before the end of the tourhalf an hour, 15 minutes and 5 minutes.

· The participant of the Olympiad must before the expiration of the time allotted for the tour to hand in your work

· It is not advisable to encrypt the tasks of the school Olympiad

· The participant can hand over the work ahead of schedule, after which he must immediately leave the location of the tour.

· the number of points for each task from 0 to 10 ( it is not recommended to enter fractional scores, they are rounded "in favor of the student"to full points).

· The jury of the Olympiad evaluates the entries given in the clean copy. Drafts are not checked sya.The correct answer given without justification or derived from incorrect reasoning is not taken into account. If the problem is not completely solved, then the stages of its solution are assessed.are evaluated in accordance with the assessment criteria for this task.

· P Verification of works is carried out by the Jury of the Olympiad according to the standard methodology for evaluating solutions:

· The list of evaluation of the work of participants

· The jury members make all notes in the work of the participant only in red ink. Points for intermediate calculations are placed near the corresponding places in the work (this excludes omission of individual items from the evaluation criteria). The final grade for the task is put at stakethe solution. In addition, a jury member enters it in a table on the first page of the work andvit his signature under the assessment.

· At the end of the check, the jury member responsible for this parallel passes the presentation supervisor of the organizing committee of the work.

· For each Olympiad task, the jury members fill out evaluation sheets (sheets). The points received by the participants of the Olympiad for the completed tasks are entered in the final table.

· Work verification protocols are posted for public viewing in a predetermined month.those after their signing by the responsible for the class and the chairman of the jury.

· Analysis of solutions to problems is carried out immediately after the end of the Olympiad.

The main purpose of this procedure- to explain to the participants of the Olympiad the main ideas of the solutioneach of the proposed tasks on the rounds, possible ways to complete the tasks, andalso demonstrate their application to a specific task. During the analysis of tasks, the participants of the Olympiad must receive all the necessary information for self-assessment of the correctness of the submitted for verification jury decisions to minimize questions to the jury about the objectivity of theirevaluation and thereby reduce the number of unfounded appeals based on the results of the verification of the decisions of all participants.

· An appeal is held in cases of disagreement of the participant of the Olympiad with the results of evaluation of his Olympiad work or violation of the procedure for holding the Olympiad.

· The time and place of the appeal is set by the Organizing Committee of the Olympiad.

· The procedure for the appeal is brought to the attention of the participants of the Olympiad beforestart of the Olympics.

· To conduct an appeal, the Organizing Committee of the Olympiad creates an appeal commissionfrom the members of the Jury (at least two people).

· The participant of the Olympiad who filed the appeal is given the opportunity to convinceis that his work is checked and evaluated in accordance with established requirements mi.

· The appeal of the participant of the Olympiad is considered on the day of showing the works.

· To conduct an appeal, the participant of the Olympiad submits a written application addressed tojury chairman.

· The participant of the Olympiad has the right to be present at the consideration of the appeal, according towho gave the statement

· The decisions of the Board of Appeal are final and not subject to revision. lie.

· The work of the Appeal Commission is documented in protocols that are signed chairman and all members of the committee.

· The final results of the Olympiad are approved by the Organizing Committee, taking into account the results the work of the appeals committee.

· The winners and prize-winners of the Olympiad are determined by the results of the decision of the participanttasks in each of the parallels (separately for 7th, 8th, 9th, 10th and 11th grades). final the result of each participant is calculated as the sum of the scores received by this participantcatches for solving each problem on the round.

· The final results of checking the decisions of all participants are recorded in the total table, which is a ranked list of participants located by in descending order of their scores. Participants with the same score are listed in alphabetical order. Based on the final table, the jury determines the winners and zeros of the Olympics.

· The chairman of the jury submits the protocol for determining the winners and prize-winners to the Organizing Committee for approval of the list of winners and prize-winners of the Physics Olympiad.

Responsible for compiling

Olympiad tasks: ____________________

____________________

_____________________

Tasks

school stage of the All-Russian Olympiad for schoolchildren in physics

1. The tourist went on a hike and covered some distance. At the same time, he walked the first half of the way at a speed of 6 km/h, for half the remaining time he rode a bicycle at a speed of 16 km/h, and the rest of the way he went uphill at a speed of 2 km/h.

Determine the average speed of the tourist during his movement.

2. The alloy consists of 100 g of gold and 100 cm3 of copper. Determine the density of this alloy. The density of gold is 19.3 g/cm3, the density of copper is 8.9 g/cm3.

1. The student measured the density of a wooden block covered with paint and found it to be 600 kg/m3. But in fact, the bar consists of two parts, equal in mass, the density of one of which is twice the density of the other. Find the density of both parts of the bar. The mass of paint can be neglected.

2. the meeting was over if either two or all three runners at once caught up with each other. Mo

1. On a circular race track from a point ABOUT Petrov andSidorov. WITH crustVx Sidorova twice the speedV2 Petrov. The race is over whenathletes simultaneously back to the point ABOUT. How many riders had meeting places, from personal from the point 01

2. To what height could a load of mass be lifted T= 1000 kg if possiblemake full use of the energy released when 1 liter of water cools down fromtx = 100°C to tx = 20 °C? Specific heat capacity of water With= 4200 J/kg*°С, water density 1000 kg/m3.

3. The volume of water in a vessel is in thermal equilibriumV = 0,5 l and a piece of ice. into a vessel they begin to pour in alcohol, the temperature of which is 0 °С, mixing content. How manyDo you need to add alcohol to melt the ice? Alcohol density rs = 800 kg/m3. Count tight sti of water and ice equal to 1000 kg/m3 and 900 kg/m3

respectively. The heat given offwhen mixing water and alcohol, ignore. Consider that the volume of the mixture of water and alcohol is equal to the sum of the volumes of the initial components.

1. Swimming at speedV past the big coral, the little fish felt danger and began to move with a constant (modulo and direction) accelerationA = 2 m/s2. Through timet= 5 safter the start of accelerated motion, its speed turned out to be directed at an angle of 90° to the initial direction of motion and was twice the initial one. Determine initial velocity modulusV, with which the fish swam past the coral.

2. During a break between laboratory work, the naughty children assembled a chain ofseveral identical ammeters and a voltmeter. From the teacher's explanation, the children firmlyremember that ammeters must be connected in series, and voltmeters in parallel. Therefore, the assembled circuit looked like this:

After turning on the current source, surprisingly, the ammeters did not burn out and even becameshow something. Some showed a current of 2 A, and some 2.2 A. The voltmeter showed a voltage of 10 V. From this data, determine the voltage at the current source, with ammeter resistance and voltmeter resistance.

3. The fishing rod float has a volumeV = 5 cm3 and mass t = 2 g. To the float a lead sinker is attached to the fishing line, and at the same time the float floats, plunging ontohalf of its volume. Find the weight of the sinker M. Density of waterp1= 1000 kg/m3, lead density p2= 11300 kg/m.

1. A master of sports, a second-class athlete and a novice ski along the ring routewith a ring length of 1 km. The competition is who will run the longest distance in 2 hours. They started at the same time in one place of the ring. Each athlete runs with its constant modulo speed. A novice running not very fast at a speed of 4 km / h noticed that every time he passes the starting point, he is sure to be overtaken both other athletes (they can overtake him in other places of the route). Other him on The observation is that when the master overtakes only the second-class player, then they are both at the maximum distance from the beginner. How many kilometers did each athletes in 2 hours? For reference: the highest average speed achieved by an athletenom at the World Championships in cross-country skiing, is approximately 26 km / h.

2. When an ideal gas is transferred from the state A into a state IN its pressure decreased in direct proportion to its volume, andtemperature dropped from 127 °С up to 51 °C. How many percentV decreased volume of gas?

3. An electrical circuit consists of a battery, a capacitor, two identical resistors, key TO and ammeter A. First the key is open, the capacitor is not charged (Fig. 17). deputies key cabins, and the charging of the capacitor begins. Determine the speedcapacitor chargingAq/ At at the moment when the currentflowing through the ammeter is 1.6 ma. It is known that the maximum currentpassed through the battery is 3 ma.

Problem solving options:

7th grade

1. The tourist went on a hike and covered some distance. At the same time, he walked at a speed of 6 km/h for the first half of the journey, rode a bicycle at a speed of 16 km/h for half the remaining time, and climbed uphill at a speed of 2 km/h for the rest of the journey. Determine the average speed of the tourist during his movement.

Then the tourist covered the first half of the way in the time

T1=L/2*6=L/12 hours

t2=T-t1/2=1/2(T-L/12).

Remaining path t3=(L-L/2-16t2)/2= L/4- 4*(T- L /12)/

T = t 1+ t 2+ t 3= L /12+ T /2- L /24+ L /4-4* T + L /3=15 L /24- T /2 3 T =5 L /12 then V \u003d L / T \u003d 36/5 \u003d 7.2 km / h

2. The alloy consists of 100 g of gold and 100 cm3 of copper. Determine the density of this alloy. The density of gold is 19.3 g/cm3, the density of copper is 8.9 g/cm3.

The weight of the alloy ism = 100+100-8,9 = 990 g. The volume of the alloy is

V = 100/19.3+100 ~ 105.2cm

Therefore, the density of the alloy is equal to p \u003d 990 / 105.2 \u003d 9.4

Answer: The density of the alloy is approximately equal to 9.4 g/cm3.

3.How many kilometers are in one nautical mile?

1. A nautical mile is defined as the length of a portion of the equator on the surface of the globe.when displaced by one arc minute. Thus, moving one nautical milu along the equator corresponds to a change in geographical coordinates by one minute of longitude.

2. Equator - an imaginary line of intersection with the surface of the Earth's plane, perpen dicular axis of rotation of the planet and passing through its center. Equator length approx.exactly equal to 40000 km.

Problem solving options:

8th grade

1. The student measured the density of a wooden block covered with paint, and it turned out to be 600 kg/m3. But in fact, the bar consists of two parts, equal in mass, the density of one of which is twice the density of the other. Find the density of both parts of the bar. The mass of paint can be neglected.

Let T- the mass of each of the parts of the bar, px And p2 = px 1 2 - their density. Thenparts of the bar have volumes T IpxAnd t/2px, and the whole bar is a mass 1t and volume t *rx.

From here we find the density of the parts of the bar:px = 900 kg/m3, p2 = 450 kg/m3.

2. Three super marathon runners start from the same place at the same time ring treadmill and 10 hours run in one direction at a constant speed: laneout 9 km/h, second 10 km/h, third 12 km/h. The length of the track is 400 m. We say that aboutthe meeting was over if either two or all three runners at once caught up with each other. MoThe starting point is not considered a meeting. How many "double" and "triple" meetings have occurred during a run? Which of the athletes most often participated in the meetings and how many times?

The second athlete runs faster than the first one by 1 km/h. This means that in 10 hours the first runner will overtake the second by 10 km, that is, there will beN\2 = (10 km)/(400 m) = 25 encounters. Similarly, the number of meetings of the first athlete with the thirdN13 (30 km) / (400 m) = 75 meetings, the second athlete with the thirdN23 = (20 km)/(400 m) = 50 encounters.

Every time the first and second runners meet, the third one ends up in the same place,means the number of "triple" meetingsN3= 25. Total number of "double" meetingsN2 = Nn + Nn+ N23 2N3 = 100.

Answer: in total there were 100 "double meetings" and 25 triple meetings; the first and third athletes met most often, this happened 75 times.

3. The tourist went on a hike and covered some distance. At the same time, he walked the first half of the way at a speed of 6 km/h, for half the remaining time he rode a bicycle at a speed of 16 km/h, and the rest of the way he went uphill at a speed of 2 km/h. Determine the average speed of the tourist during his movement.

Let the total length of the tourist path be equal to L km, and the total time of its movement is T hours.

Then the tourist covered the first half of the way in the time t1=L/ 2*6=L/12 hours

t 2= T - t 1/2=1/2(T - L /12).

Remaining path t 3=(L - L /2-16 t 2)/2= L /4- 4*(T - L /12)/

T = t 1+ t 2+ t 3= L /12+ T /2- L /24+ L /4-4* T + L /3=15 L /24-7 T /2 3 T =5 L / 12 then V \u003d L / T \u003d 36 / 5 \u003d 7.2 km / h

ABOUTThe main goals and objectives of the Olympiad are to identify and develop students' creative abilities and interest in research activities, create the necessary conditions for supporting gifted children, and promote scientific knowledge.

Lead time:

60 min -7, 8 classes - 4 tasks;

1 hour 30 min - Grade 9 - 4 tasks

2 hours - 10.11 classes - 5 tasks.

The Olympiad is held in one round of individual competitions of participants. Participants submit a report on the work done in writing. Additional oral questioning is not allowed.

To complete the tasks, students are recommended to use a calculator and a set of tables. For a successful jobin the 9th grade, it is necessary to give students a table of heat capacities and specific heat of fusion.

The jury of the Olympiad evaluates the entries given in the clean copy. Drafts are not checked. All notes in the work of the participant, the members of the jury do onlyred ink. Points for intermediate calculations are placed near the corresponding places in the work. The final score for the problem is given at the end of the solution. The jury member enters the score in the table on the first page of the work and puts his signature.

In case of an incorrect decision, it is necessary to find and mark the error that led to it.

The correct answer given without justification or obtained from incorrect reasoning is not taken into account. If the task is not completely solved, then the stages of its solution are evaluated in accordance with the evaluation criteria for this task.

The maximum number of points for the correct solution of the problem for grades 7-9 is 5 points.

Verification of works is carried out according to the standard methodology for evaluating solutions:

The maximum number of points for grades 7, 8, 9 is 20, for grades 10, 11 -25 points.

7th grade

On the image

1 futucorresponds to the distance in304.8 mm

vL\u003d 100 m, its speedu=1.5 m/s.

All-Russian Olympiad for schoolchildren in physics.

school stage. 2015-2016 academic year.

7th grade

In ancient Greece, the unit of mass was "talent". One talent contained 60 mines, and one mine was divided into 100 drachmas. The mass of the golden bowl found by archaeologists, according to ancient Greek sources, was 1 talent and 15 min. Express this value in kilograms if it is known that 1 drachma corresponds to 4.4 grams.

On the imagethe characteristic of writing paper "Snegurochka", which can be found on its packaging, is given. Determine the weight of the unpacked ream of this paper. The mass of the package can be neglected.

The navy uses a non-systemic unit of length called the foot. Knowing that1 futucorresponds to the distance in304.8 mm, estimate the distance between the ship's keel and the seabed referred to in the expression "7 feet under the keel". Give your answer in meters and round to the nearest integer.

Two people simultaneously enter the escalator from opposite sides and move towards each other with the same speed relative to the escalatorv= 2 m/s. At what distance from the end of the escalator will they meet? Escalator lengthL\u003d 100 m, its speedu=1.5 m/s.

All-Russian Olympiad for schoolchildren in physics.

school stage.

2015-2016 academic year

Answers and Quick Solutions

7th grade

1. Decision. One talent is 60*100=6000 drachmas, 15 minutes consists of 15*100=1500 drachmas. Thus, the mass of the bowl is 7500 drachmas or 7500 * 4.4 = 33000 g = 33 kg.Answer: 33 kg.

2. Solution. From the characteristics of the paper it follows that 1 m2 such paper has

weight 80 g. Then one sheet with an areaS= 0,21 * 0,297= 0.06237 m2 has massm= 80 * 0,06237 = 4.9896

Therefore, a pack of paper of 500 sheets has a massM= 500 * m=500 * 4,9896 = 2494.8 g= 2.4948 kg= 2.5 kg.Answer: 2.5 kg.

3. Solution.

7∙ 304.8 mm = 2133.6 mm

2133.6 mm = 21.336 m

21, 336 m = 21 mAnswer: 21 m.

4. Solution. A person moving "along" the escalator moves relative to the ground at a speed of 2+1.5=3.5 m/s, moving "against" the escalator at a speed of 2-1.5=0.5 m/s. The speed of their approach (which does not depend on the speed of the escalator) is 3.5+0.5=4 m/s. Relative to the ground, they will travel a path of 100 m, spending time on it. Thus, a person moving “along” the escalator will travel 3.5 m / s * 25 s = 87.5 m relative to the ground.Answer: 87.5 m from the end where the escalator "exits" from.

Keys.

School stage. Grade 7.

Duration: 2 hours.

1. The fisherman was sailing down the river in a boat, caught his hat on the bridge, and she fell into the water. An hour later, the fisherman caught himself, turned back and picked up his hat 4 km below the bridge. What is the speed of the current? The speed of the boat relative to the water remained unchanged in modulus.

Solution. It is convenient to consider the movement of the hat and boat relative to the water, because relativelythe hat is motionless in water, and the speed of the boat, when it swims from the hat to the hat, is the same modulo - just as it would be in a lake. Therefore, after the turn, the fisherman swam towards the hat too1 hour, i.e. he picked up the hat 2 hours after dropping it. According to the condition, during this time the hat floated with the current 4 km, from which it follows that the speed of the current is 2 km/h.

2. 3

Solution. cp \u003d S / t. = 30 km/h. On the second: υ

Answer: average speed all the way 60 km/h; speed in the first section 30 km/h; and on the second 80 km / h.

3. The toy bucket is 5 times smaller than the real one and has the same shape. How many toy buckets does it take to fill a real bucket?

Solution. Large bucket volume A 3 , the volume of the toy bucket A 3 /125. Number of buckets N = A 3 / A 3 /125.

Answer: 125

4. Determine the length L

Note.

Equipment.

Solution.

Let L , d , h , V S S = πR 2 ext − πR 2 ext d

All-Russian Olympiad for Schoolchildren in Physics 2012-2013.

school stage. 8th grade.

Duration: 2 hours.

1. The car traveled the first quarter of the way at a constant speed for half the entire time of movement. The next third of the way, moving at a constant speed, for a quarter of the time. The rest of the way was covered with a speed υ 3 = 100 km/h. What is the average speed of the car for the entire journey? What are the speeds in the first and second sections?

Solution. By definition, the average speed is the ratio of the entire path to the entire travel time: υ cp \u003d S / t. It follows from the condition that the length of the third section is 5/12 of the entire path, and the time is 1/4 of the total time. Therefore, υ 3 \u003d S 3 /t 3 \u003d 5/3 S / t \u003d 5/3 υ cf → u cf \u003d 3/5 u 3 → u cf \u003d 60 km / h. Speed ​​in the first section: υ 1 \u003d S 1 /t 1; υ 1 \u003d S 2 / 4 t; υ 1 \u003d 1/2 υ cf; υ 1 = 30 km/h. On the second: υ 2 \u003d S 2 /t 2; υ 2 \u003d S 4 / 3 t; υ 2 \u003d 4/3 υ cf; υ 2 \u003d 80 km / h.

2. 3

Solution. ρ = m/V

V \u003d V 1 + V 2,

V 1 \u003d m 1 / V 1

V 2 \u003d m 2 / V 2

ρ = m / V 1 + V 2 = 4/3 ρ 2

Answer: 450 and 900 kg/m 3 .

3. A rod of constant cross section, the left side of which is made of aluminum and the right side of which is made of copper, is balanced on a support. The length of the aluminum part is 50 cm. What is the length of the entire rod?

Solution. L c - rod length,

MgL / 2 \u003d mg (L c - L) / 2

ρ 1 L 2 \u003d ρ 2 (L c - L) 2

L c \u003d 0.77 m

Answer: 0.77m

4. Determine the length L insulating tape in a whole skein.

Note. From the skein, you can unwind a piece of insulating tape no more than 20 cm long.

Equipment. A roll of electrical tape, a caliper, a sheet of graph paper.

Solution

Let L , d , h , V - length, thickness, width and volume of the tape. Let S - the area of ​​​​the base of the coil of electrical tape (Fig. 1). It can be determined either “by cells” on graph paper, or from the calculation S = πR 2 external − πR 2 internal , but the last expression gives a less accurate result, since the skein can be deformed and have an oval shape. Tape thickness d measured by the series method. Then the length of the tape is

All-Russian Olympiad for Schoolchildren in Physics 2012-2013.

school stage. Grade 9

Duration: 2 hours.

1. The car of a train moving at a speed of 36 km/h was pierced by a bullet flying perpendicular to the movement of the car. One hole in the walls of the car is displaced by 3 cm relative to the other. The width of the car is 2.7 m. What is the speed of the bullet?

Solution. Let the car speed v 1 \u003d 10 m / s, displacement x \u003d 0.003 m, wagon width y \u003d 2.7 m.

t \u003d x / v 1 \u003d 0.003c v p \u003d y / t \u003d 2.7 m / 0.003 s \u003d 900 m / s

Answer: 900m/s

2. The student measured the density of the bar, and it turned out to be ρ = 600 kg/m 3 . In fact, the bar consists of two parts, equal in mass, the density of one of which is 2 times greater than the density of the other. Find the densities of both parts.

Solution. ρ = m/V

V \u003d V 1 + V 2,

V 1 \u003d m 1 / V 1

V 2 \u003d m 2 / V 2

ρ = m / V 1 + V 2 = 4/3 ρ 2

ρ 2 = 450 kg/m 3 and ρ 1 = 900 kg/m 3

Answer: 450 and 900 kg/m 3 .

Solution.

4. Measure the density of salt water.

Equipment. A solid body (a cylinder from a set of calorimetric bodies) on a thread, a dynamometer, a beaker with water, a glass of salt water.

Solution.

The expression for calculating the density of salt water is obtained from the law of Archimedes ρ=, where P 1 and P 2 respectively body weight in air and salt water.

Measure body volume with a measuring cylinder filled with water.

Measure body weight in air and salt water using a dynamometer.

Estimate measurement errors.

All-Russian Olympiad for Schoolchildren in Physics 2012-2013.

school stage. Grade 10.

Duration: 3 hours.

1. The projection of the speed of some body moving along the X axis changes with time as shown in the figure. At the moment t = 0, the body is at the origin. How far will the body be after 100 s? How far will it travel during this time?

Solution.

2. A vertical stand made of a thin rigid rod is fixed on a horizontal floor. A small wooden block of mass 180 g is resting on this support. A bullet of mass 9 g, flying in a horizontal direction with a certain speed v, hits the block. The bullet pierces the block and flies out of it at a speed of 3 m / s, after which both the block and the bullet fall to the floor. Find the ratio of the ranges of the bullet and the bar along the horizontal.

Solution.

Equipment.

Solution

All-Russian Olympiad for Schoolchildren in Physics 2012-2013.

school stage. Grade 11.

Duration: 3 hours.

1 . After vigorously shaking the bottle, in which there was a little shampoo left, it turned out to be full of foam. Determine the density of the foam, if it is known that the mass of air contained in the bottle is equal to the mass of the shampoo? Air density 1.3 g/l, shampoo 1100 g/l.

Solution.

2. A small aluminum ball with a light thread tied to it

frozen into a 100g ice cube. The free end of the thread is attached to the bottom of a heat-insulated cylindrical vessel, into which water weighing 0.5 kg and having a temperature of 20°C is poured. The temperature of the ice and the ball is 0˚С, the initial tension force of the thread is 0.08N. What will be the temperature of the water at the moment when the tension force becomes zero?

3. Four small identically charged beads of mass m each were connected by four non-conducting threads and suspended by one of the beads so that the threads coming from the suspension point formed an angle of 60˚. Determine the tension in the threads.

4 . Determine the coefficient of friction of the clothesline.

Equipment. Clothesline (cord) about 8-0 cm long, ruler (30-40 cm).

Solution. Stretch the flexible clothesline on the table perpendicular to the edge of the table. Measure the length of the rope. Gradually hang part of the rope off the table until the rope begins to slip.

Measure the length of the suspended part x at the moment of the beginning of the sliding. Since the cord (rope) has the same thickness everywhere, after transformations we obtain the calculation formula:

copper

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

Why is it impossible to squeeze a plastic bottle filled with water, but an empty plastic bottle can be squeezed easily?

How to make glass not wet with water?

A ball falls in a vertical tube filled with glycerin. At the same time, it travels a distance of 10 cm, 20 cm, 40 cm, 80 cm, respectively, in 0.5 s, 1 s, 2 s, 4 s. What is the relationship between distance traveled and time? Write a formula.

Why does sugar dissolve faster in hot tea than in cold tea?

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

Robert Ruank's bestseller Something Significant describes a situation in which the leader of an African village, wanting to know which of two people was telling the truth, ordered each to lick a hot knife. Explain why the liar used to burn his tongue.

Under which blanket will it be warmer: wadded or down?

How many times faster is a train moving at 72 km/h faster than a fly flying at 5 m/s?

The bus traveled the first half of the journey at a speed of 60 km/h and the rest of the journey at a speed of 80 km/h. Find the average physical and arithmetic average speed of its movement.

Determine the voltage at the ends of a steel conductor 140 cm long and with a cross-sectional area of ​​​​0.2 mm 2, in which the current strength is 250 mA (the resistivity of steel is 0.15 Ohm * mm 2 / m).

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

	Scientific discoveries		Names of scientists
			Lomonosov
			Torricelli
	The law of universal gravitation.
			Democritus

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

Calculate the force with which atmospheric air acts on the open palm of a person if the air pressure is 100 kPa and the area of ​​\u200b\u200bthe palm is 180 cm 2.

Why is an unexpected cold snap not dangerous for winter crops if they are under deep snow cover?

Establish a correspondence between scientific discoveries and the names of scientists to whom these discoveries belong.

	Scientific discoveries		Names of scientists
	He studied how the free fall of bodies occurs (the famous leaning tower in Italy).
	Law on the transmission of pressure by liquids and gases.		Lomonosov
	He was the first to observe the thermal (chaotic) motion of particles.		Torricelli
	The law of universal gravitation.
	For the first time I figured out how to measure atmospheric pressure.
	The first hypothesis is that all substances are made up of atoms.		Democritus
	The scientist suggested that the atom is a part of the body, not consisting of any other smaller and different bodies ...
	Buoyancy law. His famous exclamation: “Eureka! Eureka!"

1. Why does a stumbled person fall forward, while a slipped person falls back?

   How many times faster is a train moving at 36 km/h faster than a fly flying at 5 m/s?

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

Grade 10

1. The body moves along the OX axis. The projection of its speed changes according to the law given in the graph. What is the distance traveled by the body in 2 seconds?

2. The aircraft flew the first third of the way at a speed of 1100 km/h, and the rest of the way at a speed of 800 km/h. Find the average physical speed of its flight and the arithmetic average. Compare the received data.

3. The temperature of a small tin ball when dropped on a massive steel plate increased by 2°C. Neglecting the energy losses for heat transfer to surrounding bodies, determine the height from which the ball fell from the results of this experiment. The specific heat capacity of tin is 225 J/kg K. The free fall acceleration is assumed to be 10 m/s 2 .

4. A boy of mass 60 kg catches up with a sleigh of mass 40 kg moving in the same direction and jumps on them. Before the jump, the speed of the boy is 2.6 m/s, the speed of the sleigh is 2 m/s. What is the initial speed of their combined motion?

5. There are 25-watt and 100-watt light bulbs, designed for the same voltage, connected in series and connected to the network. Which one will release more heat?

Physics Olympiad 2011 - 2012 academic year

(school stage of the All-Russian Olympiad for schoolchildren)

Grade 11

1. The acceleration of a ball rolling down a smooth inclined plane is 1.2 m/s 2 . On this descent, his speed increased by 9 m/s. Determine the total time the ball descends from the inclined plane.

2. The bar lies on a rough inclined support. Three forces act on it: the force of gravity mg, the force of elasticity of the support N, the force of friction F. What is the modulus of the resultant forces of gravity and elasticity if the bar is at rest?

3. The volume of 12 mol of nitrogen in a vessel at a temperature of 300 K and a pressure of 10 5 Pa is equal to V 1. What is the volume of 1 mole of nitrogen at the same pressure and twice the temperature?

4. The length of a cylindrical copper wire is 10 times longer than the length of an aluminum wire, and their masses are the same. Find the ratio of the resistances of these conductors.

5. Why does it get hotter when you throw water on the hot stones of the stove in the steam room? Why is it necessary to add water little by little and always boil water or very hot, but not cold?

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Guidelines for conducting and evaluating the school stage of the Olympiad.docx

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At the school stage, it is recommended to include 4 tasks in the task for students in grades 7 and 8. Allocate 2 hours for their implementation; for students in grades 9, 10 and 11 - 5 tasks each, for which 3 hours are allotted.

The tasks of each age parallel are compiled in one version, so the participants must sit one at a table (desk).

Before the start of the tour, the participant fills out the cover of the notebook, indicating his data on it.

Participants complete the work with blue or purple ink pens. Pens with red or green ink are not allowed to write decisions.

During the Olympiad, the participants of the Olympiad may use a simple engineering calculator. And vice versa, the use of reference literature, textbooks, etc. is unacceptable. If necessary, students should be provided with periodic tables.

The system for evaluating the results of the Olympiad

Number of points for each task theoretical The round ranges from 0 to 10 points.

If the problem is solved partially, then the stages of solving the problem are subject to evaluation. It is not recommended to enter fractional scores. In extreme cases, they should be rounded “in favor of the student” to whole points.

It is not allowed to deduct points for “bad handwriting”, inaccurate notes, or for solving a problem in a way that does not coincide with the method proposed by the methodological committee.

Note. In general, one should not follow the author's grading system too dogmatically (these are just recommendations!). Decisions and approaches of schoolchildren may differ from the author's, be not rational.

Particular attention should be paid to the applied mathematical apparatus used for tasks that do not have alternative solutions.

An example of the correspondence of the points given and the solution given by the participant of the Olympiad

Points

Correctness (falseness) of the decision

Complete correct solution

The right decision. There are some minor flaws that do not affect the overall solution.

Selected document to view School stage of the Physics Olympiad Grade 9.docx

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Grade 9

1. Train movements.

t 1 = 23 ct 2 = 13 c

2. Calculation of electrical circuits.

R 1 = R 4 = 600 Ohm,R 2 = R 3 = 1.8 kOhm.

3. Calorimeter.

t 0 , 0 O WITH . M , its specific heat capacityWith , λ m .

4. Colored glasses.

5. Flask in water.

3 with a capacity of 1.5 liters has a mass of 250 g. What mass should be placed in a flask so that it sinks in water? Water density 1 g/cm 3 .

1. The experimenter Gluck watched the oncoming movement of an express train and an electric train. It turned out that each of the trains passed Gluck in the same time.t 1 = 23 c. Meanwhile, Gluck's friend, the theoretician Bag, was riding in an electric train and determined that the fast train passed him fort 2 = 13 c. What is the difference between train and train lengths?

Solution.

Evaluation criteria:

Recording the equation of motion of a fast train - 1 point

Recording the equation of motion of the train - 1 point

Recording the equation of motion when approaching a fast train and an electric train - 2 points

Solving the equation of motion, writing the formula in general form - 5 points

Mathematical calculations -1 point

2. What is the resistance of the circuit with the switch open and closed?R 1 = R 4 = 600 Ohm,R 2 = R 3 = 1.8 kOhm.

Solution.

With the key open:R o = 1.2 kOhm.

With the key closed:R o = 0.9 kOhm

Equivalent circuit with a closed key:

Evaluation criteria:

Finding the total resistance of the circuit with the key open - 3 points

Equivalent circuit with a closed key - 2 points

Finding the total resistance of the circuit with the key closed - 3 points

Mathematical calculations, conversion of units of measurement - 2 points

3. In a calorimeter with water, the temperature of whicht 0 , threw a piece of ice that had a temperature 0 O WITH . After the establishment of thermal equilibrium, it turned out that a quarter of the ice did not melt. Assuming that the mass of water is knownM , its specific heat capacityWith , specific heat of fusion of iceλ , find the initial mass of the piece of icem .

Solution.

Evaluation criteria:

Drawing up an equation for the amount of heat given off by cold water - 2 points

Solving the heat balance equation (writing the formula in general form, without intermediate calculations) - 3 points

Output of measurement units for checking the calculation formula - 1 point

4. On the notebook is written in red pencil "excellent" and "green" - "good". There are two glasses - green and red. Through which glass do you need to look to see the word "excellent"? Explain your answer.

Solution.

If the red glass is brought to the record with a red pencil, then it will not be visible, because red glass allows only red rays to pass through and the entire background will be red.

If we look at the record with a red pencil through a green glass, then on a green background we will see the word “excellent”, written in black letters, because. green glass does not transmit red rays of light.

To see the word "excellent" in the notebook, you need to look through the green glass.

Evaluation criteria:

Complete answer - 5 points

5. Glass flask with a density of 2.5 g/cm 3 with a capacity of 1.5 liters has a mass of 250 g. What weight should be placed in the flask so that it sinks in water? Water density 1 g/cm 3 .

Solution.

Evaluation criteria:

Writing a formula for finding the force of gravity acting on a flask with a load - 2 points

Writing the formula for finding the Archimedes force acting on a flask immersed in water - 3 points

Selected document to view School stage of the Physics Olympiad Grade 8.docx

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School stage of the Physics Olympiad.

8th grade

Traveler.

Parrot Kesha.

That morning, the parrot Keshka, as usual, was going to make a report on the benefits of banana growing and banana eating. Having had breakfast with 5 bananas, he took a megaphone and climbed to the "tribune" - to the top of a palm tree 20 meters high. Halfway through, he felt that he could not reach the top with a megaphone. Then he left the megaphone and climbed on without him. Will Keshka be able to make a report if the report needs an energy reserve of 200 J, one eaten banana allows you to do work of 200 J, the mass of a parrot is 3 kg, the mass of a megaphone is 1 kg? (when calculating, takeg= 10 N/kg)

Temperature.

O

Ice floe.

ice density

Answers, instructions, solutions to the Olympiad problems

1. A traveler traveled for 1 hour 30 minutes at a speed of 10 km/h on a camel and then for 3 hours on a donkey at a speed of 16 km/h. What was the traveler's average speed for the entire journey?

Solution.

Evaluation criteria:

Writing the formula for the average speed of movement - 1 point

Finding the distance traveled at the first stage of movement - 1 point

Finding the distance traveled at the second stage of movement - 1 point

Mathematical calculations, conversion of units of measurement - 2 points

2. That morning, the parrot Keshka, as usual, was going to make a report on the benefits of banana growing and banana eating. Having had breakfast with 5 bananas, he took a megaphone and climbed to the "tribune" - to the top of a palm tree 20m high. Halfway through, he felt that he couldn't reach the top with the megaphone. Then he left the megaphone and climbed on without him. Will Keshka be able to make a report if the report needs an energy reserve of 200 J, one eaten banana allows you to do work of 200 J, the mass of a parrot is 3 kg, the mass of a megaphone is 1 kg?

Solution.

Evaluation criteria:

Finding the total energy reserve from eaten bananas - 1 point

The energy expended to raise the body to a height h - 2 points

Energy expended by Keshka to rise to the podium and speak - 1 point

Mathematical calculations, the correct formulation of the final answer - 1 point

3. In water weighing 1 kg, the temperature of which is 10 O C, pour in 800 g of boiling water. What will be the final temperature of the mixture? Specific heat capacity of water

Solution.

Evaluation criteria:

Drawing up an equation for the amount of heat received by cold water - 1 point

Drawing up an equation for the amount of heat given off by hot water - 1 point

Recording the heat balance equation - 2 points

Solving the heat balance equation (writing the formula in general form, without intermediate calculations) - 5 points

4. A flat ice floe 0.3 m thick floats in the river. What is the height of the part of the ice floe protruding above the water? Density of water ice density

Solution.

Evaluation criteria:

Recording the swimming conditions of bodies - 1 point

Writing a formula for finding the force of gravity acting on an ice floe - 2 points

Recording the formula for finding the Archimedes force acting on an ice floe in water - 3 points

Solving a system of two equations - 3 points

Mathematical calculations - 1 point

Selected document to view School stage of the Physics Olympiad Grade 10.docx

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School stage of the Physics Olympiad.

Grade 10

1. Average speed.

2. Escalator.

The subway escalator lifts a passenger standing on it in 1 min. If a person walks along a stopped escalator, it will take 3 minutes to rise. How long will it take to get up if a person walks up an escalator moving up?

3. Ice bucket.

M With = 4200 J/(kg O λ = 340000 J/kg.

t˚,WITH

t, min

t, min minmiminmin

4. Equivalent circuit.

Find the resistance of the circuit shown in the figure.

2 R

2 R

2 R

2 R

2 R

2 R

R - ?

5. Ballistic pendulum.

m

Answers, instructions, solutions to the Olympiad problems

1 . The traveler traveled from city A to city B, first by train and then by camel. What was the traveler's average speed if he traveled two-thirds of the way by train and one-third of the way by camel? The speed of a train is 90 km/h, the speed of a camel is 15 km/h.

Solution.

Let's denote the distance between the points as s.

Then the train time is:

Evaluation criteria:

Writing a formula for finding time at the first stage of the journey - 1 point

Recording the formula for finding time at the second stage of movement - 1 point

Finding the entire time of movement - 3 points

Derivation of the calculation formula for finding the average speed (writing the formula in general form, without intermediate calculations) - 3 points

Mathematical calculations - 2 points.

2. The subway escalator lifts a passenger standing on it in 1 minute. If a person walks along a stopped escalator, it will take 3 minutes to rise. How long will it take to get up if a person walks up an escalator moving up?

Solution.

Evaluation criteria:

Drawing up an equation of motion for a passenger on a moving escalator - 1 point

Drawing up an equation of motion for a passenger moving on a stationary escalator - 1 point

Drawing up an equation of motion for a moving passenger, on a moving escalator -2 points

Solving a system of equations, finding the time of movement for a moving passenger on a moving escalator (deriving a calculation formula in a general form without intermediate calculations) - 4 points

Mathematical calculations - 1 point

3. A bucket contains a mixture of water and ice with a total mass ofM = 10 kg. The bucket was brought into the room and immediately began to measure the temperature of the mixture. The resulting dependence of temperature on time is shown in the figure. Specific heat capacity of waterWith = 4200 J/(kg O WITH). Specific heat of melting iceλ = 340000 J/kg. Determine the mass of ice in the bucket when it was brought into the room. Ignore the heat capacity of the bucket.

t˚, ˚ WITH

t, min minmiminmin

Solution.

Evaluation criteria:

Drawing up an equation for the amount of heat received by water - 2 points

Formulating an equation for the amount of heat required to melt ice - 3 points

Writing the heat balance equation - 1 point

Solving a system of equations (writing a formula in a general form, without intermediate calculations) - 3 points

Mathematical calculations - 1 point

4. Find the resistance of the circuit shown in the figure.

2 R

2 R

2 R

2 R

2 R

2 R

R - ?

Solution:

Two right resistances are connected in parallel and together giveR .

This resistance is connected in series with the rightmost resistanceR . Together they give a resistance of2 R .

Thus, moving from the right end of the circuit to the left, we get that the total resistance between the inputs of the circuit isR .

Evaluation criteria:

Calculation of parallel connection of two resistors - 2 points

Calculation of the series connection of two resistors - 2 points

Equivalent circuit diagram - 5 points

Mathematical calculations - 1 point

5. A box of mass M suspended on a thin thread is hit by a bullet of massm, flying horizontally at a speed , and gets stuck in it. To what height H does the box rise after being hit by a bullet?

Solution.

Butterfly - 8 km/h

Fly – 300 m/min

Cheetah - 112 km / h

Turtle - 6 m/min

2. Treasure.

A record about the location of the treasure was found: “From the old oak, go north 20 m, turn left and go 30 m, turn left and go 60 m, turn right and go 15 m, turn right and go 40 m; dig here. What is the path that, according to the record, one must go to get from the oak to the treasure? How far from the oak is the treasure. Complete the task drawing.

3. Cockroach Mitrofan.

Cockroach Mitrofan makes a walk around the kitchen. For the first 10 s, he walked at a speed of 1 cm/s in the direction to the north, then turned to the west and walked 50 cm in 10 s, stood for 5 s, and then in the direction to the northeast at a speed of 2 cm/s, traveled a path of length 20 see Here he was overtaken by the foot of a man. How long did the Mitrofan cockroach walk around the kitchen? What is the average speed of the cockroach Mitrofan?

4. Racing on the escalator.

Answers, instructions, solutions to the Olympiad problems

1. Write down the names of the animals in descending order of their speed of movement:

Shark - 500 m/min

Butterfly - 8 km/h

Fly – 300 m/min

Cheetah - 112 km / h

Turtle - 6 m/min

Solution.

Evaluation criteria:

Translation of the speed of the butterfly in the International System of Units - 1 point

Translation of the speed of the fly in SI - 1 point

Translation of the speed of the cheetah in SI - 1 point

Translation of the speed of the turtle in SI - 1 point

Recording the names of animals in descending order of speed - 1 point.

• Cheetah - 31.1 m/s

  Shark - 500 m/min

  Fly - 5 m / s

  Butterfly - 2.2 m/s

  Turtle - 0.1 m/s

2. A note about the location of the treasure was found: “From the old oak, go north 20 m, turn left and go 30 m, turn left and go 60 m, turn right and go 15 m, turn right and go 40 m; dig here. What is the path that, according to the record, one must go to get from the oak to the treasure? How far from the oak is the treasure. Complete the task drawing.

Solution.

Evaluation criteria:

Drawing of the trajectory plan, taking the scale: in 1cm 10m - 2 points

Finding the path traveled - 1 point

Understanding the difference between the traveled path and the movement of the body - 2 points

3. Cockroach Mitrofan makes a walk around the kitchen. For the first 10 s, he walked at a speed of 1 cm/s in the direction to the north, then turned to the west and walked 50 cm in 10 s, stood for 5 s, and then in the direction to the northeast at a speed of 2 cm/s, traveled a path of length 20 cm.

Here he was overtaken by the foot of a man. How long did the Mitrofan cockroach walk around the kitchen? What is the average speed of the cockroach Mitrofan?

Solution.

Evaluation criteria:

Finding the time of movement at the third stage of movement: - 1 point

Finding the distance traveled at the first stage of the cockroach's movement - 1 point

Writing a formula for finding the average speed of a cockroach - 2 points

Mathematical calculations - 1 point

4. Two kids Petya and Vasya decided to have a race on an escalator moving down. Starting at the same time, they ran from one point, located exactly in the middle of the escalator, in different directions: Petya - down, and Vasya - up the escalator. The time spent on the distance by Vasya turned out to be 3 times more than Petya's. How fast does the escalator move if the friends at the last competition showed the same result, running the same distance at a speed of 2.1 m/s?

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