The water exerts a force on the ship. In which direction does this force act?... (1)

Transcription

1 1. The diagram below shows an empty cargo ship. It is not moving. (a) The water exerts a force on the ship. In which direction does this force act?... (b) The diagram below shows the same cargo ship. This time it has a full load of cargo. (i) How does the force exerted by the water on the ship change as the ship is loaded? Why has the force exerted by the water changed? Bucklers Mead Community School 1

2 2. (a) When a car is driven efficiently the engine gives a constant forward pull on the car as the car accelerates to its maximum speed. During this time frictional forces and air resistance oppose the forward motion of the car. The sketch graphs below show how the car s speed increases when only the driver is in the car, and when the driver has a passenger in the car. speed driver alone driver and passenger time (i) How does the acceleration of the car change with time? What conclusion can be made about the resultant (net) forward force on the car as its speed increases? On the graph, draw a line to show how you would expect the car s speed to vary if it carried three passengers. (b) The manufacturer of a family car gave the following information. Mass of car 950g The car will accelerate from 0 to 33 m/s in 11 seconds. Bucklers Mead Community School 2

3 (i) Calculate the acceleration of the car during the 11 seconds. Answer... Calculate the force needed to produce this acceleration. Answer... N (iii) The manufacturer of the car claims a top speed of 110 miles per hour. Explain why there must be a top speed for any car. Bucklers Mead Community School 3

4 3. Below is a distance-time graph for part of a train journey. The train is travelling at a constant speed Total distance (km) Time (minutes) (a) Use the graph to find (i) how far the train travels in 2 minutes... km. how long it takes the train to travel a distance of 10 kilometres... minutes. (b) Calculate the speed of the train (4) Bucklers Mead Community School 4

5 4. (a) The diagram below shows a moving tractor. The forward force from the engine exactly balances the resisting forces on the tractor. (i) Describe the motion of the tractor.... The tractor comes to a drier part of the field where the resisting forces are less. If the forward force from the engine is unchanged how, if at all, will the motion of the tractor be affected? (3) (b) Two pupils are given the task of finding out how fast a tractor moves across a field. As the tractor starts a straight run across the field the pupils time how long it takes to pass a series of posts which are forty metres apart. The results obtained are shown in the table below. Distance travelled (m) Time taken (s) Bucklers Mead Community School 5

6 (i) Draw a graph of distance travelled against time taken using the axes on the graph below. Label your graph line A Distance (m) Time (s) Calculate the speed of the tractor (3) (c) In another, wetter field there is more resistance to the movement of the tractor. It now travels at 4 m/s. Bucklers Mead Community School 6

7 (i) Calculate the time needed to travel 200m On the graph in part (b) draw a line to represent the motion of the tractor across the second field. Label this line B. (4) (d) On a road the tractor accelerates from rest up to a speed of 6 m/s in 15 seconds. Calculate the acceleration of the tractor acceleration =...m/s² (3) 5. A sky-diver jumps from a plane. The sky-diver is shown in the diagram below. (a) Arrows X and Y show two forces acting on the sky-diver as he falls. (i) Name the forces X and Y. X... Y... Bucklers Mead Community School 7

8 Explain why force X acts in an upward direction. (iii) At first forces X and Y are unbalanced. Which of the forces will be bigger?... (iv) How does this unbalanced force affect the sky-diver? (b) After some time the sky-diver pulls the rip cord and the parachute opens. The sky-diver and parachute are shown in the diagram below. X After a while forces X and Y are balanced. Underline the correct answer in each line below. Y Bucklers Mead Community School 8

9 Force X has increased / stayed the same / decreased. Force Y has increased / stayed the same / decreased. The speed of the sky-diver will increase / stay the same / decrease. (3) (c) The graph below shows how the height of the sky-diver changes with time A 1500 B height (m) C time (s) D (i) Which part of the graph, AB, BC or CD shows the sky-diver falling at a constant speed?... What distance does the sky-diver fall at a constant speed? Distance... m Bucklers Mead Community School 9

10 (iii) How long does he fall at this speed? Time... s (iv) Calculate this speed. Speed... m/s 6. A car accelerates from rest. Its speed is measured as it accelerates. The results are shown in the table. Speed (m/s) time (s) Bucklers Mead Community School 10

11 (a) Draw a graph of speed against time on the graph paper speed (m/s) time (s) (3) (b) Calculate the acceleration of the car Acceleration... m/s 2 Bucklers Mead Community School 11

12 (c) The car eventually reached a constant speed and then travelled 350 metres in 10 seconds. Calculate the speed at which it travelled Speed... m/s Total 7 marks 7. Five forces, A, B, C, D and E act on the van. (a) Complete the following sentences by choosing the correct forces from A to E. Force... is the forward force from the engine. Force... is the force resisting the van s motion. (b) The size of forces A and E can change. Complete the table to show how big force A is compared to force E for each motion of the van. Do this by placing a tick in the correct box. The first one has been done for you. MOTION OF VAN Not moving Speeding up Constant speed Slowing down FORCE A SMALLER THAN FORCE E FORCE A EQUAL TO FORCE E FORCE A BIGGER THAN FORCE E (3) Bucklers Mead Community School 12

13 (c) When is force E zero?... (d) The van has a fault and leaks one drop of oil every second. The diagram below shows the oil drops left on the road as the van moves from W to Z. W X Y Z Describe the motion of the van as it moves from: W to X... X to Y... Y to Z... (3) (e) The driver and passengers wear seatbelts. Seatbelts reduce the risk of injury if the van stops suddenly. backwards downwards force forwards mass weight Complete the following sentences, using words from the list above, to explain why the risk of injury is reduced if the van stops suddenly. A large... is needed to stop the van suddenly. The driver and passengers would continue to move.... The seatbelts supply a... force to keep the driver and passengers in their seats. (3) 8. (a) A cyclist goes on a long ride. The graph shows how the distance travelled changes with time during the ride E Distance in km B C D 10 A Time in hours Bucklers Mead Community School 13

14 (i) Between which two points on the graph was the cyclist moving at the fastest speed?... State one way cyclists can reduce the air resistance acting on them (iii) How long did the cyclist stop and rest?... (iv) Write down the equation which links distance, speed and time.... (v) Calculate, in km/hr, the average speed of the cyclist while moving Average speed =... km/hr (3) (b) For part of the ride the cyclist pushed on the pedals with a constant vertical force of 300 N. The simplified diagrams show the pedals in three different positions. 300 N 300 N 14 cm 16 cm 300 N 16 cm A B C (i) Which position, A, B, or C, gives the largest moment on the pedal?... Bucklers Mead Community School 14

15 Use the following equation to calculate, in Newton metres, the size of the largest moment on the pedal. moment = force perpendicular distance from pivot Moment =... Nm (Total 10 marks) 9. A hot air balloon called Global Challenger was used to try to break the record for travelling round the world. The graph shows how the height of the balloon changed during the flight A B F height (metres) C E D time after burners were lit (hours) The balloon took off from Marrakesh one hour after the burners were lit and climbed rapidly. Bucklers Mead Community School 15

16 (a) Use the graph to find: (i) the maximum height reached. Maximum height... metres. the total time of the flight. Total time... hours. (b) Several important moments during the flight are labelled on the graph with the letters A, B, C, D, E and F. At which of these moments did the following happen? (i) The balloon began a slow controlled descent to 2500 metres.... The crew threw out all the cargo on board in order to stop a very rapid descent.... (iii) The balloon started to descend from 9000 metres.... (3) 10. The diagram below shows the orbits for two types of satellite, a polar orbit and a geostationary orbit. geostationary orbit polar orbit (a) A satellite in stable Earth orbit moves at a constant speed in a circular orbit because there is a single force acting on it. (i) What is the direction of this force? What is the cause of this force? (iii) What is the effect of this force on the velocity of the satellite? Bucklers Mead Community School 16

17 (iv) In which of the orbits shown above would this force be bigger? Explain the reason for your answer. (v) Explain why the kinetic energy of the satellite remains constant. (b) A satellite in a geostationary orbit takes about 24 hours to complete one orbit, whilst one in a low polar orbit typically takes 90 minutes. (i) Suggest, with reasons, one use of a satellite in a geostationary orbit. Suggest, with reasons, one use of a satellite in a polar orbit. (c) Sometimes the motion of a rocket in space has to be changed. The diagram below shows such a rocket being accelerated. payload fuel fuel Bucklers Mead Community School 17

18 Use your ideas of momentum to explain why the rocket accelerates (4) 11. (a) points correct; 2 line correct each (b) increases 1 (c) (i) ecf 1 (iii) increased ecf 1 [6] 12. (a) (i) decreases 1 decreases 1 (iii) lower speed everywhere 1 (b) (i) 3 a = s or a = 33 t 11 gains 1 mark 1 ms 2 1 gains 1 mark 2850 ecf 2 gains 2 marks else working gains 1 mark (iii) air resistance/frictional forces increase with speed; 2 till frictional force = max forward engine force; when acceleration is zero (incorrect statement - 1 mark) or (limitation on maximum speed for safety-1 mark) any two each [9] 13. (a) (i) 3km [allow 2.9 to 3.1] 1 Bucklers Mead Community School 18

19 6.6 min [allow 6.5 to 6.8] 1 (b) can be in any units, 1.5 km/min, 1500 m/min, 25 m/s, 90 km/h 4 Sp = d/t =12/8 =1.5 km/min each (see marking of calculations) 14. (a) (i) Constant speed 2 Accelerates to higher constant speed (b) (i) Points correct (allow one major or two minor mistakes) 2 Line correct (for their points) 5 m/s 3 or 5 gets 2 marks or correct unit gets 1 mark mark (c) (i) 50 s 3 or 50 gets 2 marks or t = d/v gets 1 mark Line correct (of gradient 4 and spans 30 consecutive seconds) 1 (d) (i) or 6/15 gets 2 marks or a = v/t gets 1 mark [15] 15. (a) (i) air resistance/drag/friction (or upthrust) 1 weight/gravitational pull/gravity each air resistance/friction acts in opposite direction to motion 1 (iii) Y 1 (iv) the sky-diver accelerates/his speed increases 2 in downward direction/towards the Earth/falls each Bucklers Mead Community School 19

20 (b) force X has increased 3 force Y has stayed the same the speed of the sky-diver will stay the same each (c) (i) CD (iii) 50 (but apply e.c.f. from (i)) 2 (iv) 10 (but apply e.c.f. from and (iii)) 2 gets 2 marks or 500/50 or d/t gets 1 mark [14] 16. (a) (i) C and D or D and C 1 accept CD accept DC accept answers in terms of time any one from: 1 streamline position streamline clothes accept crouched position accept tight clothes accept design of cycle accept cycle slower 0.5 hours or 30 minutes 1 or 1800 seconds must have unit distance (iv) speed = time (taken) accept any correct rearrangement accept s = d/t or v s/t accept velocity for speed 1 accept d s t if subsequent use of correct (v) 16 3 allow for mark for each of time = 3.5 hours distance = 56km allow e.c.f. from part (a)(iii) if correctly used an answer of 14 gains 2 marks allow 1 mark for correct attempt to average the three sections (b) (i) C 1 Bucklers Mead Community School 20

21 48 2 an answer of gains 1 mark if answer (b)(i) is given as A then 42 scores 1 mark 4200 scores 0 marks substitution of correct figures = 1 mark [10] 17. (a) A then E 1 for one mark (b) A > E 3 A = E A < E in this order each (c) when van stops / is stationary / is parked 1 for one mark (d) WX slowing down (owtte) 3 XY constant speed (owtte) YZ speeding up (owtte) each (e).. force. forwards. backwards 3 each [11] 18. (a) (i) 9400(m) (hours) 1 (b) (i) F 1 D 1 (iii) B 1 [5] 19. (a) (i) towards Earth 1 gravity 1 (iii) changes direction 1 (iv) polar orbit; 2 closer each (v) speed constant 2 Bucklers Mead Community School 21

22 mass constant each (b) (i) communications satellite/is stationary relative to Earth surface 2 or always beams to same area on Earth (no credit if reversed or inconsistent) each spy/weather satellite/gathering sensible information 2 scans much of surface quickly each (c) momentum conserved; 4 spent fuel has momentum to right; rocket gets equal momentum to left; therefore rocket speed increases - consequential each [15] 20. (a) up 1 (b) (i) increased 1 more water displaced; 1 ship heavier either [3] Bucklers Mead Community School 22