Summer holiday homework Physics Year 9/10 1 (a) The figure below shows two students investigating reaction time. Student A lets the ruler go. Student B closes her hand the moment she sees the ruler fall. This investigation can be used to find out if listening to music changes the reaction times of a student. Explain how. (4) (b) A second group of students used a stop clock and computer simulation test to measure their reaction times. The table below shows their results. 1
Student Reaction time in seconds Test 1 Test 2 Test 3 X 0.44 0.40 0.34 Y 0.28 0.24 0.22 Z 0.36 0.33 0.47 Give one conclusion that can be made from the results for student X and student Y. (c) Test 3 for student Z gave an anomalous result. Suggest two possible reasons why this anomalous result occurred. 1... 2... (Total 7 marks) 2 Figure 2 shows a skier using a drag lift. The drag lift pulls the skier from the bottom to the top of a ski slope. The arrows, A, B, C and D represent the forces acting on the skier and her skis. Figure 2 (a) Which arrow represents the force pulling the skier up the slope? 2
Tick one box. A B C D (b) Which arrow represents the normal contact force? Tick one box. A B C D (c) The drag lift pulls the skier with a constant resultant force of 300N for a distance of 45 m. Use the following equation to calculate the work done to pull the skier up the slope. work done = force distance Work done =... J (d) At the top of the slope the skier leaves the drag lift and skis back to the bottom of the slope. Figure 2 shows how the velocity of the skier changes with time as the skier moves down the slope. Figure 2 3
After 50 seconds the skier starts to slow down. The skier decelerates at a constant rate coming to a stop in 15 seconds. Draw a line on Figure 2 to show the change in velocity of the skier as she slows down and comes to a stop. (Total 6 marks) 3 Two children, A and B, are sitting on a see-saw, as shown in the figure below. The see-saw is balanced. (a) Use the following equation to calculate the moment of child B about the pivot of the see-saw. moment of a force = force distance Give your answer in newton-metres Moment =...Nm 4
(b) Use the idea of moments to explain what happens when child B moves closer to the pivot. (3) (Total 5 marks) 4 The figure below shows the forces acting on a child who is balancing on a pogo stick. The child and pogo stick are not moving. (a) The downward force of the child on the spring is equal to the upward force of the spring on the child. This is an example of which one of Newton s Laws of motion? Tick one box. First Law Second Law 5
Third Law (b) Complete the sentence. Use an answer from the box. elastic potential gravitational potential kinetic The compressed spring stores... energy. (c) The child has a weight of 343 N. Gravitational field strength = 9.8 N / kg Write down the equation which links gravitational field strength, mass and weight. (d) Calculate the mass of the child. kg Mass =... (3) (e) The weight of the child causes the spring to compress elastically from a length of 30cm to a new length of 23cm. Write down the equation which links compression, force and spring constant. (f) Calculate the spring constant of the spring. Give your answer in newtons per metre. / m Spring constant =... N 6
(4) (Total 11 marks) 5 A student suspended a spring from a laboratory stand and then hung a weight from the spring. Figure 1 shows the spring before and after the weight is added. Figure 1 (a) Measure the extension of the spring shown in Figure 1. mm Extension =... (b) The student used the spring, a set of weights and a ruler to investigate how the extension of the spring depended on the weight hanging from the spring. Before starting the investigation the student wrote the following prediction: The extension of the spring will be directly proportional to the weight hanging from the spring. Figure 2 shows how the student arranged the apparatus. Figure 2 7
Before taking any measurements, the student adjusted the ruler to make it vertical. Explain why adjusting the ruler was important. (c) The student measured the extension of the spring using a range of weights. The student s data is shown plotted as a graph in Figure 3. Figure 3 What range of weight did the student use? 8
...... (d) Why does the data plotted in Figure 3 support the student s prediction?............ (e) Describe one technique that you could have used to improve the accuracy of the measurements taken by the student......................... (f) The student continued the investigation by increasing the range of weights added to the spring. All of the data is shown plotted as a graph in Figure 4. Figure 4 9
At the end of the investigation, all of the weights were removed from the spring. What can you conclude from Figure 4 about the deformation of the spring? Give the reason for your conclusion. (Total 9 marks) 6 A train travels from town A to town B. Figure 1 shows the route taken by the train. Figure 1 has been drawn to scale. Figure 1 (a) The distance the train travels between A and B is not the same as the displacement of the train. What is the difference between distance and displacement? (b) Use Figure 1 to determine the displacement of the train in travelling from A to B. Show how you obtain your answer. 10
Displacement =... km Direction=... (c) There are places on the journey where the train accelerates without changing speed. Explain how this can happen. (d) Figure 2 shows how the velocity of the train changes with time as the train travels along a straight section of the journey. Figure 2 Estimate the distance travelled by the train along the section of the journey shown in Figure 2. To gain full marks you must show how you worked out your answer. 11
Distance =... m (3) (Total 8 marks) 7 A drum is hit by a beater attached to a drumstick lever. The drumstick lever is attached to a foot-pedal by a chain, as shown below. (a) State how the size of the force of the chain on the foot-pedal compares with the size of the force of the toe on the foot-pedal. (b) The foot-pedal is pushed halfway down and held stationary. The force of the toe and the force of the chain each create a moment which acts on the foot-pedal. Compare the size and direction of the moments of the toe and the chain. Tick ( ) one box. Size Direction Tick ( ) The moments are equal The moments are equal The moment of the force of the toe is greater same opposite same (c) How can the drummer create a greater moment about the pivot without increasing the force he applies? 12
(Total 3 marks) 8 In a balancing game, wooden blocks are used to build a tower. The shape of the tower at the start of the game is shown in Figure 1. During the game, some of the blocks are taken out and put on top of the tower as shown in Figure 2. This causes the centre of mass of the tower to change. Figure 1 Figure 2 (a) (i) State what is meant by the term centre of mass....... (ii) Give two reasons why the tower in Figure 2 is less stable than the tower in Figure 1. 1.... 2.... (b) Figure 3 shows a different arrangement for the wooden blocks. Figure 3 13
A block was placed in position A and an identical block was placed in position B at the same time. Explain why the tower did not fall over. You should include reference to moments in your answer. (Total 5 marks) 9 (a) Figure 1 shows the forces acting on a model air-powered rocket just after it has been launched vertically upwards. (i) How does the velocity of the rocket change as the rocket moves upwards? Give a reason for your answer. (ii) The velocity of the rocket is not the same as the speed of the rocket. What is the difference between the velocity of an object and the speed of an object? 14
(b) The speed of the rocket just after being launched is 12 m / s. The mass of the rocket is 0.05 kg. (i) Calculate the kinetic energy of the rocket just after being launched. Kinetic energy =... J (ii) As the rocket moves upwards, it gains gravitational potential energy. State the maximum gravitational potential energy gained by the rocket. Ignore the effect of air resistance. Maximum gravitational potential energy =... J (iii) Calculate the maximum height the rocket will reach. Ignore the effect of air resistance. Gravitational field strength = 10 N / kg. Maximum height =... m (iv) Figure 2 shows four velocity time graphs. 15
Taking air resistance into account, which graph, A, B, C or D, shows how the velocity of the rocket changes as it falls from the maximum height it reached until it just hits the ground? Write the correct answer in the box. (c) The rocket can be launched at different angles to the horizontal. The horizontal distance the rocket travels is called the range. Figure 3 shows the paths taken by the rocket when launched at different angles. Air resistance has been ignored. What pattern links the angle at which the rocket is launched and the range of the rocket?............ 16
10 (a) Figure 1 shows a car travelling around a bend in the road. The car is travelling at a constant speed. There is a resultant force acting on the car. This resultant force is called the centripetal force. (i) In which direction, A, B, C or D, does the centripetal force act on the car? Tick ( ) one box. A B C D (ii) State the name of the force that provides the centripetal force. (iii) State two factors that affect the size of the centripetal force acting on the car. 1... 2... 17
(b) Figure 2 shows a racing car. braverabbit/istock/thinkstock The racing car should not roll over when racing. State two features of the car that make it difficult for the car to roll over. 1...... 2...... (Total 6 marks) 11. Before a new bus can be used on the roads, it must pass a stability test. Figure 1 shows how the bus is tested. 18
(a) (i) The bus will topple over if the ramp is tilted at too great an angle. Explain why. (ii) The bus is tested to angles of tilt far greater than it would experience in normal use. Suggest two reasons why. 1... 2... (b) Figure 2 shows the hydraulic machine that is used to make the ramp tilt. The pressure applied to the hydraulic liquid at the master piston is the same as the pressure applied by the hydraulic liquid to the slave piston. (i) State the property of the liquid that keeps the pressure at both pistons the same. 19
(ii) A 360 N force acts on the master piston. Use information from Figure 2 to calculate the force applied by the hydraulic liquid to the slave piston. Force =... N (3) (Total 8 marks) 20
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