Name: _______________________________________________ 	

  	
  	
Forces & Momentum - higher	

 	
Date:	

  	
  	
Time: I hour	
  	
Total marks available: 60 marks	
  	
Total marks achieved: ______ 	

  	

  	

  	

  	

  	

  	

  	

	

 

Questions

Q1.
 
Some quantities are vectors, others are scalars.
(a)  Complete the table ticking the boxes to show which quantities are vectors and which are scalars.
One has been done for you.
(2)

(b)  A car travels at 20 m/s.
The mass of the car is 1500 kg.
(i)  State the equation linking momentum, mass and velocity.
(1)

(ii)  Calculate the momentum of the car.
(2)

momentum = ........................................................... kg m/s

(c)  In a crash test, a car runs into a wall and stops.

The momentum of the car before the crash is 22500 kg m/s.
The car stops in 0.14 s.
(i)  Calculate the average force on the car during the crash.
(2)

average force = ........................................................... N

(ii)  Use ideas about momentum to explain how seat belts can reduce injuries to passengers during a crash.
(3)
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(Total for question = 10 marks)

Q2.
 
This question is about collisions.
The diagram shows ball A moving in the direction shown by the arrow.
Ball A collides with ball B, a stationary ball of the same mass and size as ball A.

(a)  State the principle of conservation of momentum.
(1)
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(b)  Ball A collides with ball B.

·	 before the collision, ball A moves with a velocity of 10 m/s
·	 after the collision, ball B moves in the same direction as ball A with a velocity of 8 m/s
·	 ball A continues to move in the same direction, but at a lower velocity 
Calculate the velocity of ball A after the collision. 
[mass of each ball = 0.16 kg]
(3)

velocity of ball A = ........................................................... m/s
(c)  During the collision some kinetic energy is lost.
Calculate the kinetic energy lost in the collision.

(3)

kinetic energy lost = ........................................................... J
 
(Total for question = 7 marks)
 
Q3.
 
(a)  The diagram shows a coin being dropped from a height.

The graph shows how the velocity of the coin changes until it hits the ground.

(i)  State the equation linking acceleration, change in velocity and time.
(1)

(ii)  The coin hits the ground in a time of 0.62 s with a velocity of 6.1 m/s.
Calculate the acceleration of the coin as it falls.
Give the unit.
(3)

 acceleration = ................ unit ................ 
(iii)  State the feature of the graph that shows this acceleration.
(1)
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(iv)  Calculate the height from which the coin was dropped.
Use the graph to help with your calculation.
(3)

height = ........................................................... m
(b)  A ball is dropped from a very large height.
The graph shows how the velocity of the ball changes until just before it hits the ground.

Explain why the velocity of the ball changes in this way.
Refer to ideas about forces in your answer.
(5)
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(Total for question = 13 marks)

Q4.

A bowling ball rolls for 3 s and hits a pin.

The graph shows how the velocity of the ball changes with time.

(a) How can the graph be used to find the distance that the ball rolls before it hits the pin?
(1)
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(b) The mass of the ball is 6.4 kg.
(i) State the equation linking momentum, mass and velocity.
(1)

(ii) Calculate the momentum of the ball before it hits the pin.
Give the unit.
(3)

Momentum = ........................................................... Unit ...........................................................

(c) (i) What is the velocity of the ball after it hits the pin?
(1)

Velocity = ........................................................... m/s

(ii) After the collision, the ball and the pin have the same velocity.
Calculate the mass of the pin.
(3)

Mass = ........................................................... kg

(Total for question = 9 marks)

Q5.

Scientists test the safety features of a car by crashing it into a large block of concrete.
A dummy is placed in the driver's seat and the scientists video the crash.

(a) In one test, the dummy and the car travel at 8 m/s.
The mass of the dummy is 72 kg.
Calculate the momentum of the dummy.
(2)

Momentum = ........................................................... kg m/s

(b) In another test, the momentum of the dummy changes by 920 kg m/s in a time
of 0.17 s.
Calculate the average horizontal force acting on the dummy during this time.
(2)

Average force = ........................................................... N

(c) These tests help to make our roads safer.
(i) State two factors that affect the stopping distance of a car driven on a road.
(2)
1 .....................................................................................................................................................................................................
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(ii) Use ideas about momentum to explain how the crumple zone of a car helps to
reduce injuries during a crash.
(3)
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(Total for question = 9 marks)

Q6.

A student is playing a game with some empty tins.

(a) He throws a wet cloth of mass 0.15 kg at the tins.
The wet cloth moves at a velocity of 6.0 m/s.
(i) State the equation linking momentum, mass and velocity.
(1)

(ii) Calculate the momentum of the wet cloth and give the unit.
(3)

Momentum = ........................................................... unit. ...........................................................

(iii) The wet cloth sticks to tin 1.

The mass of tin 1 is 0.050 kg.
The cloth and tin 1 move away together.
Calculate their velocity.
(2)

Velocity = ........................................................... m/s

(b) The student throws a bigger wet cloth at the remaining tins.
This wet cloth sticks to tins 2 and 3 and they move away together.

The student concludes

Do you agree with this conclusion?
Explain why.
(2)
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(Total for question = 8 marks)

Q7.
 
Some cars have a pedestrian airbag for safety.

If a pedestrian is hit and lands on the front of the car, the airbag inflates.

Use ideas about momentum to explain how this airbag can reduce injuries to pedestrians.
(4)

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(Total for Question = 4 marks)

Mark Scheme

Q1.

Q2.

 

Q3.

 

Q4.

Q5.

Q6.

Q7.