- Sec1 Sci P7f EQ … · Web viewSec1 Sci P7f EQ 76marks All L7 Forces and speed Q# 1/Q13.A...

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Sec1 Sci P7f EQ 76marks All L7 Forces and speedQ# 1/ Q13. A sky-diver jumped out of an aeroplane. After falling for some time she opened her parachute. The graph below shows how the speed of the sky-diver changed from the moment she jumped out of the aeroplane until she landed on the ground.

(a) What happened at 180 seconds and at 360 seconds after the sky-diver jumped out of the aeroplane?

180 seconds ………………………………………………………………………..

360 seconds ………………………………………………………..………………2 marks

(b) There was an increase in air resistance on the sky-diver as her speed increased.Explain how the graph shows this.

……….………………………………………………………………………………1 mark

(c) Two sections of the graph show where the air resistance was equal and opposite to the sky-diver’s weight. Which sections are they?

Give the letters.

…………………… and …………………1 mark

(d) (i) Use the graph to estimate how far the sky-diver fell between 180 s and 360 s.

…………………………………………………………………………………1 mark

(ii) Why can this only be an approximate figure?

…………………………………………………………………………………1 mark

Maximum 6 marks

Patrick Brannac www. Smashing Science.org of 18

http://www.SmashingScience.org/

Q# 2/ Q14. Speed cameras are used to detect motorists who break the speed limit. A number of lines 2 m apart are painted on the road. As a speeding car crosses the painted lines, the camera takes two photographs, 0.5 s apart.

(a) (i) How far did the car move between the two photographs?Give the correct unit.

............................................................................................................1 mark

(ii) How fast is the car in the photographs moving?

..................................................................................................... m/s1 mark

(b) It takes 0.0002 s to take each photograph.How far does the car move while the speed camera is taking one photograph?

..............................................................................................................… m1 mark

Q# 3/ Q16. A man does a ‘bungee jump’ over a lake. He jumps from point A with an elasticated rope tied to his ankles. The rope reaches down to point B when it is not being stretched.

The man falls past B, and the rope begins to stretch. He falls past point C to point D, which is the lowest point he reaches. Then he begins to move upwards again. Eventually he comes to rest at point C.

(a) (i) At which point, A, B, C or D, is the man whenthe tension in the rope is greater than his weight? ...............................

1 mark

(ii) At which point, A, B, C or D, is the man whenthe tension in the rope is equal to his weight? .....................................

1 mark



(b) The graph shows how the man’s speed varies with time as he falls from point A to point D and bounces back upwards.

The point when the man jumped from A has been labelled on the curve.Label the points on the curve when the man was at points B, C and D as he fell.

3 marksQ# 4/ Q17.

A bell in a church tower is attached to a wheel of radius 0.8 m. The bell is balanced upside down. The bell-ringer pulls the rope with a force of 50 N.

(b) The bell turns. When the rope is travelling at its highest speed, it moves 0.5 m in 0.04 s.What speed is this? Give the unit.

......................................................................................................................

......................................................................................................................2 marks

Q# 5/ Q19.(a) The ‘two second rule’ is a rule for car drivers. The rule is as follows:

‘Leave enough space between you and the vehicle in front so that you can pull up safely if it suddenly slows down or stops… A two second time gap may be sufficient… Use stationary objects (eg lamp-posts) to help you keep a two second gap.’

(The Highway Code, 1993)

(i) The traffic is moving at 20 m/s, and a driver is keeping to the ‘two second rule’.What is the distance between the driver and the car in front?

..........................................................................................................1 mark



(ii) The traffic increases its speed to 25 m/s, but the driver stays the same distance from the car in front.She sees the car in front pass a lamp post.How long will it take her to reach the same lamp post?

........................................................................................................s1 mark

(b) The driver decides to check her speedometer while driving along a motorway.She measures how long it takes her to travel 6 km. It takes her exactly 4 minutes.What was her speed in km/h? Show your working.

....................................................................................................................

............................................................................................................ km/h2 marks

Q# 6/ Q2. A cyclist and a runner have a race.The distance-time graph for the race is shown below.

Use the graph to answer the following questions.

(a) (i) How much time did it take the cyclist to travel 100 m?

........... s1 mark

(ii) When the cyclist finished the race how far behind was the runner?

........... m1 mark

(iii) How much more time did the runner take compared with the cyclist to complete the race?

........... s1 mark



(b) The cyclist is travelling at a constant speed between 3 seconds and 6 seconds.

How does the graph show this?

........................................................................................................................1 mark

(c) (i) When the race started, a walker set off at a steady speed of 2m/s.

Draw a line on the graph on the opposite page to show the distance covered by the walker in the first 15 seconds. Use a ruler.

1 mark

(ii) Calculate how much time it will take for the walker to walk 100m.

............................................................................................................ s1 mark

Q# 7/ Q20. The graph shows the speed of a ball as it falls from a height and bounces from the floor.

(a) The ball starts to fall and speeds up until it hits the floor.

(i) For how many seconds does the ball fall before it first hits the floor?

.............................................................................................................1 mark

(ii) Calculate the average speed of the ball during its fall.

.............................................................................................................1 mark

(iii) Calculate the height above the floor from which the ball was dropped.

.............................................................................................................1 mark

(b) (i) What is happening to the ball in the time between points A and C on the graph?

.............................................................................................................1 mark

(ii) In which direction is the ball moving between points C and D?

.............................................................................................................1 mark



(c) Calculate how high the ball bounces back up from the floor.

....................................................................................................................1 mark

(d) How long after the ball was dropped would you expect it to hit the floor for the second bounce?

....................................................................................................................1 mark

Q# 8/ Q23. The graph shows the results of a test in which a car accelerates to its maximum speed.

(a) (i) Describe how the acceleration of the car changes after the car has started to move.

............................................................................................................1 mark

(ii) How does the resultant force on the car change?

............................................................................................................1 mark

The car has a mass of 1000 kg and the maximum forward force on the car, produced by the engine, is 4000 N.

It is claimed that the car will accelerate from 0 to 24 m/s in 6 seconds.

(b) Use calculations, with the correct units, to show that the claim is false.

......................................................................................................................

......................................................................................................................

......................................................................................................................3 marks

Q# 9/ Q29. Oliver clamped a wooden plank to a desk. There was a 40 cm overhang as shown in diagram 1.



Oliver added masses to the end of the wooden plank as shown in diagram 2.

He measured the sag.

The graph below shows his results.

(a) What measurements would Oliver need to take to work out the sag?

........................................................................................................................1 mark

(b) Oliver repeated his test with a new plank with an 80 cm overhang. His results are

shown below.

mass (g) sag (cm)0 1.0

500 15.0

1000 25.0

1500 31.0

2000 35.0



(i) Plot the results from Oliver’s second test on the grid above.

Use the points to draw a line of best fit.2 marks

(ii) In the second test the plank sagged with no mass added to it.

Explain what caused this sag.

...............................................................................................................1 mark

(c) Compare the results of Oliver’s two tests.

(i) How are the results similar for each test?

...............................................................................................................1 mark

(ii) How are the results different in the second test?

...............................................................................................................1 mark

Q# 10/ Q3. (a) Satish poured some water into a long tank in the school laboratory.He used a plunger at one end to make a wave.

not to scale

(i) The wave travelled to the other end of the tank.The speed of the wave was 2 m/s.

How long did the wave take to travel to the other end?

............................................................................................................ s1 mark

Q# 11/ Q4. The drawing below shows a space buggy on the surface of Mars.

(a) The distance between Earth and Mars is 192 000 000 km.

It took a spacecraft 200 days to take the buggy from Earth to Mars.

Calculate the speed at which the spacecraft travelled.

Give the unit.



.........................................................................................................................

.........................................................................................................................2 marks

(b) The weight of the buggy was 105 N on Earth and 40 N on Mars.

Why was the weight of the buggy less on Mars than on Earth?

.........................................................................................................................1 mark

Q# 12/ Q5 The lift in a tall building hangs from a strong cable. The movement of the lift is affected by only two forces.

These forces are the tension in the cable and the weight of the lift.

(a) The lift is not moving. How do the sizes of the two forces compare?

Tick the correct box.

1 mark

(b) When the lift is moving upwards and its speed is increasing, how do the sizes of the two forces compare?

......................................................................................................................1 mark

(c) When the lift is moving upwards at a constant speed, how do the sizes of the two forces compare?

......................................................................................................................1 mark

(d) Near the top of the building the lift is moving upwards, but slowing down.

How do the sizes of the two forces now compare?

......................................................................................................................1 mark



Q# 13/ Q5. The shuttle is a spacecraft which is used to take satellites into space.The drawing below shows the shuttle just about to take off.

(c) The graph below shows how the upward force and the weight of the shuttle,including fuel, change during the first 20 seconds, after the fuel is ignited.

Why does the total weight of the shuttle decrease during the first 20 seconds?

.........................................................................................................................1 mark

(d) (i) Look at the graph. At 20 seconds, what is the value of:

the upward force on the shuttle?

............. millions of N

the total weight of the shuttle and fuel?



............. millions of N1 mark

(ii) At 20 seconds, what is the resultant force on the shuttle?

............. millions of N1 mark

(iii) Use the graph to explain why the shuttle cannot take off before10 seconds.

...............................................................................................................1 mark

Q# 14/ Q6.(a) Megan was doing time-trials on her bike around a 400 metre horizontal track.

(i) She took 32 seconds to travel 400 m.What was her average speed? Give the unit.

................ .........................................1 mark

(ii) Compare the forward force on the bike with the backward force on the bike when Megan was travelling at a constant speed.

........................................................1 mark

(b) Megan then crouched down over the handlebars to make herself more streamlined, as shown below.She continued to pedal with the same force as before.

Compare the forward and backward forces on Megan and her bike now.

.....................................................................................................................1 mark

Explain your answer.

.....................................................................................................................1 mark

Q# 15/ Q7. Anil sits on a mat at the top of a helter-skelter and then slides down a chutearound the outside.

(a) (i) Name two of the forces acting on Anil as he slides from point A to point B.

1. ....................................................................

2. ....................................................................2 marks

(ii) As Anil slides from point A to point B, the forces acting on him are balanced.

Describe Anil's speed when the forces acting on him are balanced.



.............................................................................................................1 mark

(b) Anil goes back for a second go. This time he sits on a smooth cushion instead of a mat.

He goes much faster on the cushion. Give the reason for this.

.....................................................................................................................1 mark

(c) On his third go Anil lies back on the cushion with his arms by his side.

What happens to his speed? Give the reason for your answer.

.....................................................................................................................

.....................................................................................................................2 marks

Q# 16/ Q8. A remote-controlled car was timed over a period of 10 seconds.A graph of distance against time is shown below.

(a) Describe the motion of the car between:

(i) 2 seconds and 6 seconds;

.............................................................................................................1 mark

(ii) 9 seconds and 10 seconds.

.............................................................................................................1 mark

(b) Calculate the average speed of the car between 0 and 10 seconds.Give the unit.

.....................................................................................................................



.....................................................................................................................2 marks

(c) The diagram below shows two of the forces acting on the car when it is moving.

(i) When the motor was switched off, the car slowed down and then stopped.

While the car was slowing down, which of the following was true? Tick the correct box.

1 mark

(ii) Use the graph to find the time when the car started to slow down.

The car started to slow down after ............ s.1 mark

Q# 17/ Q9. Nazia is investigating how easily a block of wood slides along a wooden bench. The diagram shows her experiment.



(a) Nazia does the experiment with different weights on top of the block. She counts how many slotted masses she needs to hang from the string to make the block of wood slide. Her results are shown in the table.

(i) Describe how the number of slotted masses needed to move the block varies with the weight on top of the block.

............................................................................................................1 mark

(ii) Nazia does the experiment with a weight of 3.5 N on top of the block of wood.

How many slotted masses would she need to make the block slide?

......................1 mark

(b) Nazia does her experiment again. This time she slides the block of wood over a sheet of glass instead of the bench top.

(i) Suggest how her results would be different this time.

............................................................................................................1 mark

(ii) Using the same sheet of glass and block of wood, and keeping the same weight on top, suggest one way Nazia could reduce the force of friction.

............................................................................................................1 mark



Mark SchemeQ# 1/ Q13.(a) 180 seconds: the parachute opened

1360 seconds: she landedanswers must be in the correct orderdo not accept ‘her speed dropped’

1(b) any one from• the slope of the graph decreases or the curve gets less steep• the graph begins to level out• the acceleration gets lessaccept ‘it curves between A and B’

1(c) B and Dletters may be in either orderboth letters are required for the mark

1(d) (i) any answer between 1000 m and 1350 mthe unit is required for the mark

1(ii) because its speed takes time to reach 6 m/saccept ‘because the speed is not constant’• because it was slowing down at first• because the speed is difficult to readaccept ‘because the speed may not be exactly 6 m/s’accept ‘because the graph curves at the corner’

1

Q# 2/ Q14. (a) (i) 16 munit required for the mark

1(ii) 32consequential marking appliesaccept answer to(a)(i) ÷ 0.5

1(b) 0.0064accept ‘6.4 mm’ or ‘0.64 cm’ consequential marking appliesaccept answer to (a)(ii) × 0.0002 s

1(c) it is scattered from the car or the road or the linesaccept ‘it is reflected’ or ‘it bounces off

1

Q# 3/ Q16. (a) (i) D1

(ii) C1

(b)

one mark each for correctly labelling B, C and Daccept B anywhere on the curve between 3.3 and 4.3 cm from AC is at the highest point on the curveD is at the point where the speed is zero

3(c) zero from A to B

1increases from B to Daccept ‘increases after B’do not accept ‘it increases’accept ‘it is zero from A to B and thenincreases’ for both marks

1[7]

Q# 4/ Q17. (b) 12.5accept ‘0.5 ÷ 0.04’ unless followed by an incorrect answer

1 (L7) m/s or m s–1

accept ‘1250 cm/s’ for both marks1 (L7)

Q# 5/ Q19.(a) (i) 40consequential marking applies

1 (L7)(ii) 1.6accept answer (a) (i) ÷ 25

1 (L7)(b) 1.5 km/min

accept ‘4 min = h’ or ‘0.067h’1 (L7)

1.5 × 60 = 90

accept ‘6 ÷ = 90’ or ‘6 ÷ 0.067 = 90’award both marks for a correct answereven if no working is shown

1 (L7)[4]

Q# 6/ Q2.(a) (i) a number from 8.0 to 8.2 s (inclusive)

1 (L6)(ii) a number from 34 to 36 m (inclusive)

1 (L7)(iii) 4 saccept response in the range 3.7–4.3

1 (L7)(b) the slope or gradient is constant



accept ‘it is a straight line’do not accept ‘the line is flat’accept ‘steady increase’

1 (L7)(c) (i) points (0, 0) and (15, 30) joined by a straight lineaccept points drawn to ± 1 mm

1 (L7)(ii) 50

accept 1 (L7)

Q# 7/ Q20.(a) (i) 0.5 or 0.5 saccept ‘0.49’

1(ii) 2.5 m/s or 21/2 m/sunits required for the mark

1(iii) 1.25 m or 11/4 mconsequential marking applies in this partaccept answer to (a) (i) × answer to (a) (ii)unit required for the markaccept ‘5 /4 m’ or ‘1 /2 × 0.5 × 5 m’

1(b) (i) any one from• it is bouncingaccept ‘hitting the floor and bouncing’• it is in contact with the flooraccept ‘hitting or touching the floor’ or ‘on the ground’accept ‘it is changing direction or velocity or speed’

1(ii) upwardsaccept ‘up’do not accept ‘up and then down’

1(c) 0.8 m or 80 cmunit required for the markaccept ‘1/2

× 0.4 × 4 m’1

(d) 1.3 sunit required for the markaccept ‘0.8 s after the bounce’or ‘0.4 s after reaching maximum height’

1[7]Q# 8/ Q23. (a) (i) it decreasesaccept ‘it is fast at the beginning and then slows down’accept ‘it is constant at first and then decreases’do not accept ‘it increases at first and then decreases’

1(ii) it decreases

1(b) units are required for each of the calculation markEITHER• maximum possible accelerationaccept ‘4000 ÷ 1000 = 4 m/s2’is 4 m/s2 or 4 m s–2

1• average acceleration is 4 m/s2 or 4 m s–2

accept ‘24 ÷ 6 = 4 m/s2’1

• average acceleration will be less than the maximum due to frictionor due to the mass of the driver

1OR• maximum possible acceleration = 4 m/s2 or 4 m s–2

accept ‘4000 ÷ 1000 = 4 m/s2’• maximum speed after 6 s is 24 m/s or 24 m s–1

accept ‘4 × 6 = 24 m/s’• actual speed will be less than this due to frictionor due to the mass of the driverOR• maximum possible acceleration = 4 m/s2 or 4 m s–2

accept ‘4000 ÷ 1000 = 4 m/s2’• minimum time to reach 24 m/s is 6 saccept ‘24 ÷ 4 = 6 s’• actual time will be more than this due to frictionor due to the mass of the driverOR• average acceleration is 4 m/s2 or 4 m s–2

accept ‘24 ÷ 6 = 4 m/s2’• average force is 4000 Naccept ‘4 × 1 000 = 4000 N’• force from the engine must be more than this to overcome friction

[5]Q# 9/ M29. (a) any one from• the original height of the plank and the height with massesaccept ‘take the height with the mass added awayfrom the height of the table’• the height of the plank before and after adding massesaccept ‘take the height of the plank with the massadded away from the height with no mass’accept ‘vertical distance moved’‘distance moved’ is insufficient

1 (L7)(b) (i) • five points plotted to within one small square

1 (L7)• smooth curve of best fit



accept an appropriate straight line of best fit1 (L7)

(ii) any one from• the weight or mass of the (wooden) plank‘the weight or mass’ is insufficient• the (larger) overhang

1 (L7)(c) (i) • as the mass increases the sag increasesaccept the converseaccept ‘the lines both went up’accept ‘sag increases in both’

1 (L7)(ii) any one from• there is more sag for each massaccept ‘the plank sags more’• the increase in sag is not constantaccept ‘in the second test they did not go up in equal amounts’• the increase in sag gets lessaccept ‘first test gives a straight line, the second was a curve’accept ‘first went up gradually, the second went up steeply’‘the plank sagged before he added any mass’ is insufficient

1 (L7)[6]

Q# 10/ Q3. (a) (i) • 0.75 s

accept ‘ ’ or ‘ ’1 (L7)

Q# 11/ Q4. (a) • 960.000

accept 1 (L7)

• km/day or kilometres per day or km day–1

accept ’40.000 km/hr’ for two marksaccept ’11.1 km/s’ for two marksaccept ’11.111 m/s’ for two marksaccept ‘d’ for ‘day’ and ‘h’ for ‘hour’do not accept ‘km pday’

1(b) • gravity on Mars is lessaccept ‘gravity is greater on Earth’

1 (L6)Q# 12/ M5. (a) The tension equals the weight.

if more than one box is ticked, award no mark1 (L6)

(b) tension is greater than weightaccept ‘tension is bigger’ or ‘weight is less’or ‘the upward force is bigger’or ‘the downward force is smaller’

1 (L6)(c) tension equals weightaccept ‘they are the same’

1 (L6)(d) tension is less than weightaccept ‘tension is less ‘or ‘weight is more’or ‘the upward force is less’or ‘the downward force is bigger’

1 (L6)[4]

Q# 13/ Q5. (a) any one from• liquids or they take up less spaceaccept ‘particles are closer together in a liquid’• liquids or they are denseraccept ‘particles are further apart in a gas’do not accept liquids are heavier’‘liquids are easier to transport’ is insufficient

1 (L7)(b) there is no oxygen in spaceaccept ‘there is no air in space’accept ‘space is a vacuum’

1 (L7)(c) any one from• the weight of the fuel decreases‘gravity gets weaker’ is insufficient• there is less fuel on board• fuel is being used upaccept ‘hydrogen and oxygen or oxygen is being used up’• water is releasedaccept ‘waste gas is given off’

1 (L7)(d) (i) • 27both answers are required for the mark • 16.5accept a number from 16.3 to 16.7

1 (L6)(ii) 10.5accept the difference between the numbers given in d iconsequential marking applies

1 (L7)(iii) any one from• up to 10 seconds the weight is greater than the (upward) force• after 10 seconds there is a resultant or net (upward) force• after 10 seconds the (upward) force is greater than the weightaccept the converseanswers must be in terms of a comparison‘it does not have a great enough upward force’ is insufficient‘at 10 seconds the forces are equal’ is insufficient

1 (L7)[6]

Q# 14/ Q6.(a) (i) 12.5 m/s



accept ‘ ’ m/s’accept ‘metres per second’ or ‘ms–1’ for m/sthe unit is required for the markdo not accept ‘mps’

1 (L7)(ii) they are equal or the sameaccept ‘they are balanced’

1 (L7)(b) the forward force is greater than the backward forceaccept the converseaccept ‘the forward force is greater’or ‘the backward force is smaller’do not accept ‘the forward force becomes greateror increases’

1 (L7)any one from• because air resistance or drag is smaller or reducedaccept ‘less friction’• because there is a smaller surface area‘she is more streamlined’ is insufficientas it is given in the question

1 (L7)[4]

Q# 15/ Q7.(a) (i) any two from• gravity or weight• friction• reactionaccept ‘upthrust’• air resistanceaccept ‘drag’do not accept ‘centrifugal force’or ‘centripetal force’ or ‘g- force’

2 (L6)(ii) any one from• constant speed• steady speed• it stays the sameaccept ‘it is the same’ or ‘it does not change’

1 (L6)(b) friction is less‘it is smoother’ or ‘it is slippery’ are insufficient

1 (L5)(c) it increasesaccept ‘he goes more quickly’

1 (L6) because there is less air resistance or friction

accept ‘he is streamlined or aerodynamic’1 (L6)

[6]Q# 16/ Q8. (a) (i) constant speed or steady speedaccept not accelerating

1 (L7)(ii) stationary or not moving or stoppedaccept ‘steady speed of zero’do not accept ‘it has a steady speed’

1 (L7)(b) 1.8

accept 1 (L7)

m/saccept ‘metres per second’ or ‘ms–1’do not accept ‘mps’

1 (L7)(c) (i) The forward force was zero and friction was greater than zero. if more than one box is ticked, award no mark

1 (L7)(ii) 6accept answers from 5.8 to 6.2

1 (L7)Q# 17/ M9. (a) (i) any one from• when the weight increases, the number of masses increasesaccept ‘they increase together’ or ‘they decrease together’• the number of masses goes down if the weight goes down• the number of masses increases with weight

1(ii) 12

1(b) (i) she would need fewer massesaccept ‘it would slide more easily’do not accept ‘less friction’

1(ii) put oil or water on the glassaccept a named lubricant for oilaccept ‘lubricate the surfaces’accept ‘polish the block of wood’accept ‘put the block of wood on rollersor ball bearings’or on any objects used as rollersdo not accept ‘tilt the glass’

1[4]



- Sec1 Sci P7f EQ … · Web viewSec1 Sci P7f EQ 76marks All L7 Forces and speed Q# 1/Q13.A...

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