Q1. The diagram below shows water falling from a dam. Each minute kg of water falls vertically into the pool at the bottom.

Transcription

1 Physics P2 Higher Questions Part 1 Q1. The diagram below shows water falling from a dam. Each minute kg of water falls vertically into the pool at the bottom. The time taken for the water to fall is 2 s and the acceleration of the water is 10 m/s². (a) Assume the speed of the water at the bottom of the dam is zero. Calculate the speed of the water just before it hits the pool at the bottom (b) Use your answer to part (a) to calculate the average speed of the falling water.... (c) Calculate the height that the water falls Page 1

2 (d) What weight of water falls into the pool each minute? (e) How much work is done by gravity each minute as the water falls? (f) A small electrical generator has been built at the foot of the waterfall. It uses the falling water to produce electrical power. (i) How much energy is available from the falling water each minute? How much power is available from the falling water? (iii) If the generator is 20% efficient, calculate the electrical power output of the generator. (4) (Total 13 marks) Page 2

3 Q2. Stars are formed from massive clouds of dust and gases in space. (a) What force pulls the clouds of dust and gas together to form stars? (b) Once formed a star can have a stable life for billions of years. Describe the two main forces at work in the star during this period of stability. (c) What happens to this star once this stable period is over? (4) (d) Suggest what might then happen to a planet close to this star. (Total 8 marks) Q3. The circuit diagram below shows a circuit used to supply electrical energy to the two headlights of a car. Page 3

4 The current through the filament of one car headlight is 3.0 A. The potential difference across each of the two headlights is 12 V. (a) Suggest a suitable fuse for the circuit.... (b) Calculate the resistance of the headlight filament when in use. Answer... W (c) Calculate the power supplied to the two headlights of the car. Answer... W (d) The fully charged car battery can deliver 72 kj of energy at 12 V. How long can the battery keep the headlights fully on? Page 4

5 Answer... s (Total 7 marks) Q4. The diagram below shows two balls on the bowling green. Ball A is moving with a velocity of 4 m/s, and is about to collide with ball B which is stationary. Both balls have a mass of 1.5 kg. After the collision both balls move to the right but the velocity of A is now 1 m/s. (a) (i) Calculate the momentum of ball A just before the collision. Answer... kg m/s What is the total momentum of balls A and B after the collision? Answer... kg m/s (iii) Calculate the momentum of ball A just after the collision. Page 5

6 Answer... kg m/s (iv) Calculate the momentum of ball B just after the collision. Answer... kg m/s (v) Calculate the velocity of ball B just after the collision. Answer... m/s (b) Calculate the loss of kinetic energy in the collision. Answer... J (3) (Total 8 marks) Q5. The diagram below shows water falling over a dam at the end of a reservoir. The water falls a vertical distance of 10 m. Page 6

7 (a) Calculate the potential energy of 1 kg of water at the top of the waterfall. Answer... J (b) What will be the kinetic energy of 1 kg of the water just before it lands in the pool? Answer... J (c) Use your answer to (b) to calculate the speed of the water as it lands at the bottom of the waterfall. Answer... m/s (3) (Total 6 marks) Page 7

8 Q6. The diagram below shows an experiment where a pendulum swings backwards and forwards. A pendulum is a small heavy weight suspended by a light string. (a) (i) In which position, A, B or C, does the pendulum have least potential energy? Explain your answer. In which position, A, B or C, does the pendulum have greatest kinetic energy? Explain your answer. (iii) After a few minutes the size of the swings becomes smaller. Explain why this happens. Page 8

9 (b) If the experiment were repeated on the Moon the pendulum would swing more slowly. Suggest a reason for this. (Total 5 marks) Q7. The diagram below shows how one type of fuel gauge in a car works. A sliding contact makes contact with a resistance wire wound in a coil (rheostat). It is connected to a float via a pivot P. When the petrol level changes the circuit resistance changes. This causes the pointer in the fuel gauge to move and show how much petrol is in the petrol tank. The circuit diagram is shown below. Page 9

10 The petrol gauge is an ammeter. Explain why the reading on the ammeter falls as the petrol is used (Total 3 marks) Q8. The table contains typical data for an oil tanker. (i) Write down the equation which links acceleration, force and mass. Page 10

11 Calculate the deceleration of the oil tanker. Show clearly how you work out your answer. Deceleration =... m/s 2 (Total 3 marks) Q9. Radon is a radioactive gas. Radon makes a major contribution to background radiation levels. Radon atoms decay by the emission of alpha particles. (a) (i) What is an alpha particle?... From which part of the radon atom does the alpha particle come?... (b) (i) A sample of air contains radon atoms. The half-life of radon is four days. Draw a graph to show how the number of radon atoms present in a sample of air will change over a period of 12 days. Page 11

12 (3) After 20 days, how many of the radon atoms from the original sample of air will have decayed? Show clearly how you work out your answer. Number of radon atoms decayed =... (3) (c) Fairly constant concentrations of radon gas have been found in some deep mine shafts. (i) Suggest why the concentration of radon gas remains fairly constant although the radon gas decays. Explain why the long term exposure to large concentrations of radon gas could be a danger to health. Page 12

13 (Total 11 marks) Q10. (a) Most of the Sun is hydrogen. Inside the core of the sun, hydrogen is being converted to helium. What name is given to this process and why is the process so important? (c) Describe what will happen to the Sun as the core runs out of hydrogen (3) (Total 5 marks) ## The table shows the braking distances for a car at different speeds and kinetic energy. The braking distance is how far the car travels once the brakes have been applied. Page 13

14 Braking distance in m Speed of car in m/s Kinetic energy of car in kj (a) A student suggests, the braking distance is directly proportional to the kinetic energy. (i) Draw a line graph to test this suggestion. (3) Does the graph show that the student s suggestion was correct or incorrect? Give a reason for your answer. Page 14

15 (iii) Use your graph and the following equation to predict a braking distance for a speed of 35 metres per second (m/s). The mass of the car is 800 kilograms (kg). Show clearly how you obtain your answer. kinetic energy = ½ mv 2 Braking distance =... m (iv) State one factor, apart from speed, which would increase the car s braking distance. (b) The diagram shows a car before and during a crash test. The car hits the wall at 14 metres per second (m/s) and takes 0.25 seconds (s) to stop. (i) Write down the equation which links acceleration, change in velocity and time taken. Calculate the deceleration of the car. Deceleration =... m/s 2 Page 15

16 (iii) In an accident the crumple zone at the front of a car collapses progressively. This increases the time it takes the car to stop. In a front end collision the injury to the car passengers should be reduced. Explain why. The answer has been started for you. By increasing the time it takes for the car to stop, the... (Total 11 marks) Q12. (a) A radiation detector and counter were used to detect and measure the radiation emitted from a weak source. The graph shows how the number of counts recorded in one minute changed with time. (i) Even though the readings from the counter were accurately recorded, not all the points fit the smooth curve. What does this tell us about the process of radioactive decay? Page 16

17 After ten minutes the number of counts recorded each minute is almost constant. Explain why. (b) The radioactive isotope sodium-24 injected into the bloodstream can be used to trace blood flow to the heart. Sodium-24 emits both beta particles and gamma rays. (i) What is a beta particle? What is a gamma ray? (iii) The count rate from a solution containing sodium-24 decreases from 584 counts per minute to 73 counts per minute in 45 hours. Calculate the half-life of sodium-2.2. Show clearly how you work out your answer. Half-life =... hours (3) (iv) Give one advantage of using sodium-24 to trace blood flow compared to using an isotope with a half-life of: [A] ten years;... [B] ten seconds.... Page 17

18 (Total 10 marks) Q13. (a) The picture shows two ice hockey players skating towards the puck. The players, travelling in opposite directions, collide, fall over and stop. (i) Use the following equation and the data given in the box to calculate the momentum of player number 3 before the collision. Show clearly how you work out your answer and give the unit. momentum = mass velocity Momentum of player 3 =... (3) What is the momentum of player 4 just before the collision? Page 18

19 (iii) The collision between the two players is not elastic. What is meant by an elastic collision? (b) The pictures show what happened when someone tried to jump from a stationary rowing boat to a jetty. Use the idea of momentum to explain why this happened (c) The diagram shows one type of padded body protector which may be worn by a horse rider. Page 19

20 If the rider falls off the horse, the body protector reduces the chance of the rider being injured. Use the idea of momentum to explain why (3) (Total 10 marks) ## (a) The table shows the half-life of some radioactive isotopes. Radioactive isotope magnesium-27 sodium-24 sulphur-35 cobalt-60 Half-life 10 minutes 15 hours 87 days 5 years Page 20

21 (i) What is meant by the term radioactive? Which one of the isotopes in the table could form part of a compound to be used as a tracer in medicine? Explain the reason for your choice. (3) (iii) Draw a graph to show how the number of radioactive atoms present in the isotope cobalt-60 will change with time. (3) (b) Nuclear power stations provide about 17% of the world s electricity. They add less than 1% to the total background levels of radiation. Some people are opposed to the use of nuclear fuels for the generation of electricity. Explain why. Page 21

22 (3) (Total 10 marks) Q15. The graph shows how the distance travelled by a car changes with time during a short journey. (i) Describe fully the motion of the car during the first two minutes of the journey. Page 22

23 (3) During the last minute of the journey the velocity of the car changes although the speed remains constant. How is this possible? (Total 4 marks) Q16. (a) What is the principle of conservation of momentum? (b) The diagram shows a simplified aircraft jet engine. Adapted from GCSE Physics by Tom Duncan. John Murray (Publishers) Ltd. (i) What is the function of the turbine? Page 23

24 Explain how the engine produces a forward thrust. (4) (c) During flight, air enters the engine at 175 m/s and leaves at 475 m/s. A forward thrust of 105 kn is produced. Use the following equation to calculate the mass of air passing through the engine every second. (Ignore the mass of the burned fuel.) Mass of air =... kg (Total 9 marks) Q17. (i) Explain how stars like the Sun were formed. Page 24

25 The Sun is made mostly of hydrogen. Eventually the hydrogen will be used up and the Sun will die. Describe what will happen to the Sun from the time the hydrogen is used up until the Sun dies. (3) (Total 5 marks) Q18. (a) The diagram shows an electric fence, designed to keep horses in a field. When a horse touches the wire the horse receives a mild electric shock. Explain how.... Page 25

26 (b) The diagram shows how a person could receive an electric shock from a faulty electrical appliance. Using a residual circuit breaker (RCB) can help to protect the person against receiving a serious shock. Current to earth (i) Compare the action of an RCB to that of a fuse. The graph illustrates how the severity of an electric shock depends upon both the size of the current and the time for which the current flows through the body. Page 26

27 Within how long must the RCB cut off the current if the person using the lawnmower is to be in no danger of serious injury? Time =... milliseconds (Total 6 marks) ## (a) The table gives information about five radioactive isotopes. Isotope Type of radiation emitted Half-life Californium-241 alpha (α) 4 minutes Cobalt-60 gamma (γ) 5 years Hydrogen-3 beta (β) 12 years Strontium-90 beta (β) 28 years Technetium-99 gamma (γ) 6 hours Page 27

28 (i) What is an alpha (α) particle? What is meant by the term half-life? (iii) Which one of the isotopes could be used as a tracer in medicine? Explain the reason for your choice. (3) (b) The increased use of radioactive isotopes is leading to an increase in the amount of radioactive waste. One method for storing the waste is to seal it in containers which are then placed deep underground. Page 28

29 Some people may be worried about having such a storage site close to the area in which they live. Explain why (3) (Total 8 marks) Q20. The radioactive isotope, carbon-14, decays by beta (β) particle emission. (a) What is a beta (β) particle? Page 29

30 (b) Plants absorb carbon-14 from the atmosphere. The graph shows the decay curve for 1 g of carbon-l4 taken from a flax plant. Use the graph to find the half-life of carbon-l4. You should show clearly on your graph how you obtain your answer. Half-life =... years. (c) Linen is a cloth made from the flax plant. A recent exhibition included part of a linen shirt, believed to have belonged to St. Thomas à Becket, who died in Extracting carbon-14 from the cloth would allow the age of the shirt to be verified. If 1 g of carbon-14 extracted from the cloth were to give 870 counts in 1 hour, would it be possible for the shirt to have once belonged to St. Thomas à Becket? You must show clearly the steps used and reason for your decision (3) (Total 6 marks) Page 30

31 Q21. The diagram shows an orbiter, the reusable part of a space shuttle. The data refers to a typical flight. (a) (i) What name is given to the force which keeps the orbiter in orbit around the Earth?... Use the following equation to calculate the kinetic energy, in joules, of the orbiter while it is in orbit. kinetic energy = ½ mv 2 Kinetic energy =... joules (iii) What happens to most of this kinetic energy as the orbiter re-enters the Earth s atmosphere? Page 31

32 (b) After touchdown the orbiter decelerates uniformly coming to a halt in 50 s. (i) Give the equation that links acceleration, time and velocity.... Calculate the deceleration of the orbiter. Show clearly how you work out your answer and give the unit. Deceleration =... (c) (i) Give the equation that links acceleration, force and mass. Calculate, in newtons, the force needed to bring the orbiter to a halt. Show clearly how you work out your answer. Force =... newtons (Total 9 marks) Q22. (a) The graph shows how a sample of barium-143, a radioactive isotope with a short half-life, decays with time. Page 32

33 (i) What is meant by the term isotope? What is meant by the term half-life? Page 33

34 (iii) Use the graph to find the half-life of barium-143. Half-life =... seconds (b) Humans take in the radioactive isotope carbon-14 from their food. After their death, the proportion of carbon-14 in their bones can be used to tell how long it is since they died. Carbon-14 has a half-life of 5700 years. (i) A bone in a living human contains 80 units of carbon-14. An identical bone taken from a skeleton found in an ancient burial ground contains 5 units of carbon-14. Calculate the age of the skeleton. Show clearly how you work out your answer. Age of skeleton =... years Why is carbon-14 unsuitable for dating a skeleton believed to be about 150 years old? (c) The increased industrial use of radioactive materials is leading to increased amounts of radioactive waste. Some people suggest that radioactive liquid waste can be mixed with water and then safely dumped at sea. Do you agree with this suggestion? Explain the reason for your answer Page 34

35 (3) (Total 9 marks) Q23. Read the information in the box and then answer the questions. Igneous rocks contain potassium-40. This is a radioactive isotope. It has a half-life of 1300 million years. Potassium-40 decays into argon-40 which is stable. Argon escapes from molten rock. Any argon found in an igneous rock must have been produced since the rock solidified. A sample of an igneous rock has one atom of potassium-40 for every three atoms of argon-40. (i) What fraction of the potassium-40 has not yet decayed? Calculate the age of the rock. Age of rock =... million years (Total 2 marks) Page 35

36 Q24. The molten rock flowing from an erupting volcano can reach a speed of 8 m/s. (i) Write down the equation that links kinetic energy, mass and speed. Calculate the kinetic energy of 1 tonne of molten rock flowing at 8 m/s. (1 tonne = 1000 kg) Kinetic energy =... joules (Total 2 marks) Q25. (a) When two objects collide, and no other forces act, then conservation of momentum applies. (i) What does the term conservation of momentum mean? Apart from collisions and similar events, give another type of event in which conservation of momentum applies. (iii) Write, in words, the equation which you need to use to calculate momentum. Page 36

37 (iv) The diagram shows a straight and horizontal runway and two trolleys, X and Y, which can move on the runway. X has a mass of 0.2 kg and its velocity is 1.2 m/s to the right. Y has a mass of 0.1 kg and is stationary. When X collides with Y they stick together. Calculate the velocity of the trolleys after the collision. Show clearly how you work out your answer and give the unit and direction. Velocity of the trolleys =... (5) (v) What assumption did you make in order to calculate your answer to part (a)(iv)? (b) Just before it hits a target, a bullet has a momentum of 5 kg m/s. It takes s for the target to stop the bullet. Calculate the force, in newtons, needed to do this. Write, in words, the equation that you will need to use and show clearly how you work out your answer. Force =... newtons (3) Page 37

38 (Total 13 marks) Q26. A machine is used to lift materials on a building site. (a) (i) Write down the equation that links change in gravitational potential energy, change in vertical height and weight. A 25 kg bag of cement is lifted from the ground to the top of the building. Calculate the gain in the gravitational potential energy of the bag of cement. (On Earth a 1 kg mass has a weight of 10 N.) Change in gravitational potential energy =... joules (b) The conveyor belt delivers six bags of cement each minute to the top of the Page 38

39 building. (i) Calculate the useful energy transferred by the machine each second. Useful energy transfer each second =... J The machine is 40% efficient. Use the following equation to calculate the total energy supplied to the machine each second. Show how you work out your answer. Total energy supplied each second =... J (Total 6 marks) Q27. (a) Uranium-234 ( 234 U) is a radioactive element. The graph shows the number of protons and neutrons in the nuclei of the elements formed when uranium-234 decays. Page 39

40 (i) How does the graph show that uranium-234 ( 234 U) and thorium-230 ( 230 Th) emit alpha particles? What makes uranium and thorium different elements? (iii) Radioactive decay may also produce gamma radiation. Why does the emission of gamma radiation not cause a new element to be formed? (b) The graph shows how the thickness of different materials needed to absorb 90% of the gamma radiation emitted by a source depends on the energy of the radiation. The energy of the gamma radiation is given in units called electron-volts. Page 40

41 (i) Which of the materials shown is least effective at absorbing gamma radiation? Use the information in the graph to give a reason for your answer. For gamma radiation of energy 1.5 million electron-volts, how many times more effective is steel than water at absorbing the radiation? Show clearly how you obtain your answer. (c) Scientists in the early twentieth century thought that atoms were made up of electrons scattered inside a ball of positive charge. This was called the plum-pudding model of the atom. Page 41

42 Plum pudding model Rutherford and Marsden did an experiment, in which a beam of alpha particles was aimed at a thin sheet of gold. Explain how the results of this experiment led to a new model of the atom. You may include one or more diagrams in your answer (3) (Total 9 marks) Page 42

43 Q28. Stars do not stay the same forever. (a) Over billions of years the amount of hydrogen in a star decreases. Why? (b) Describe how a massive star (at least five times bigger than the Sun) will change at the end of the main stable period. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. (4) (c) The inner planets of the solar system contain atoms of the heaviest elements. (i) Where did these atoms come from? What does this tell us about the age of the solar system compared with many of the stars in the Universe? (Total 7 marks) Page 43

44 Q29. The diagram shows a badge used to monitor radiation. It measures the amount of radiation a worker has been exposed to in one month. (i) What is used inside the badge to detect radiation?... What would indicate that the worker has been exposed to a high level of radiation as opposed to a low level of radiation? (iii) Why is it important to monitor the amount of radiation the worker has been exposed to? (Total 3 marks) Page 44

45 Q30. A beta particle is a high-energy electron. (i) Which part of an atom emits a beta particle?... How does the composition of an atom change when it emits a beta particle?... (Total 2 marks) Q31. (a) The diagram shows a hammer which is just about to drive a nail into a block of wood. The mass of the hammer is 0.75 kg and its velocity, just before it hits the nail, is 15.0 m/s downward. After hitting the nail, the hammer remains in contact with it for 0.1 s. After this time both the hammer and the nail have stopped moving. (i) Write down the equation, in words, which you need to use to calculate momentum. Page 45

46 What is the momentum of the hammer just before it hits the nail? Show how you work out your answer and give the units and direction. Momentum =... (3) (iii) What is the change in momentum of the hammer during the time it is in contact with the nail? (iv) Write down an equation which connects change in momentum, force and time. (v) Calculate the force applied by the hammer to the nail. Show how you work out your answer and give the unit. Force =... (3) (b) A magazine article states that: Wearing a seat belt can save your life in a car crash. Use your understanding of momentum to explain how this is correct. Page 46

47 (4) (Total 13 marks) Q32. The diagram shows a 12 volt lighting system. Each lamp has a power of 32 watts. (i) Write down the equation that links current, potential difference and power. Calculate the input current to the lighting system. Show clearly how you work out your answer Page 47

48 current =... A (Total 3 marks) Q33. (a) Explain how stars produce energy. (b) What evidence is there to suggest that the Sun was formed from the material produced when an earlier star exploded? (c) It is thought that gases from the massive star Cygnus X-1 are spiralling into a black hole. (i) Explain what is meant by the term black hole. Page 48

49 What is produced as the gases from a star spiral into a black hole? (Total 6 marks) Q34. (a) Nuclear power stations use the energy released by nuclear fission to generate electricity. (i) Explain what is meant by nuclear fission. How does nuclear fission lead to a chain reaction? You may give your answer as a labelled diagram. (b) Although nuclear fuels are relatively cheap the total cost of generating electricity using nuclear fuels is expensive. Why? Page 49

50 (c) The table compares the energy released from 1 kg of coal and 1 kg of uranium. Coal 29 MJ 1 MJ = joules Uranium MJ State one benefit to the environment of using a concentrated fuel like uranium to generate electricity rather than using the energy from coal. (Total 5 marks) Q35. (a) Nuclear power stations use the energy released by nuclear fission to generate electricity. (i) Explain what is meant by nuclear fission. How does nuclear fission lead to a chain reaction? You may give your answer as a labelled diagram. Page 50

51 (b) Although nuclear fuels are relatively cheap the total cost of generating electricity using nuclear fuels is expensive. Why? (c) The table compares the energy released from 1 kg of coal and 1 kg of uranium. Coal 29 MJ 1 MJ = joules Uranium MJ State one benefit to the environment of using a concentrated fuel like uranium to generate electricity rather than using the energy from coal. (Total 5 marks) Page 51