1.	A cyclist rides around a circular track at a uniform speed. Which of the following correctly gives the net horizontal force on the cyclist at any given instant of time?

	Net horizontal force along direction of motion	Net horizontal force normal to direction of motion	
A.	zero	zero	
B.	zero	non zero	
C.	non zero	zero	
D.	non zero	non zero	
(Total 1 mark)

2.	This question is about circular motion.
	A ball of mass 0.25 kg is attached to a string and is made to rotate with constant speed v along a horizontal circle of radius r = 0.33 m. The string is attached to the ceiling and makes an angle of 30° with the vertical.

(a)	(i)	On the diagram above, draw and label arrows to represent the forces on the ball in the position shown.
(2)

(ii)	State and explain whether the ball is in equilibrium.
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(2)
 
(b)	Determine the speed of rotation of the ball.
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(3)
(Total 7 marks)

3.	A particle of mass m is moving with constant speed v in uniform circular motion. What is the total work done by the centripetal force during one revolution?
A.	Zero
B.	
C.	mv2
D.	2πmv2
(Total 1 mark)

4.	A stone attached to a string is moving in a horizontal circle. The constant speed of the stone is v.
The diagram below shows the stone in two different positions, X and Y.
		
	Which of the following shows the direction of the change of velocity of the stone when moving from position X to position Y?

(Total 1 mark)

5.	A particle P is moving anti-clockwise with constant speed in a horizontal circle.
	Which diagram correctly shows the direction of the velocity v and acceleration a of the particle P in the position shown?

(Total 1 mark)

6.	A ball moves along the inside of a horizontal semi-circular ring as shown. The diagram is a view from above.
		
	Which arrow represents the direction of the average force on the ball?

(Total 1 mark)

7.	This question is about circular motion and global warming.
(a)	A car is travelling at constant speed of 18 m s–1 around a horizontal bend in the road.
The mass of the car is 1.5 × 103 kg and the bend forms part of a circle of radius
2.0 × 103 m.
(i)	State why the car is accelerating.
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(1)

(ii)	Determine the frictional force between the tyres of the car and the surface of the road that produces the acceleration.
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(2)
 
(b)	It is suggested that the use of fossil fuels to power cars has led to an enhancement of the greenhouse effect.
(i)	State the reason for this suggestion.
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(1)
 
(ii)	Outline one mechanism by which the enhanced greenhouse effect may lead to an increase in global warming.
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(3)
(Total 7 marks)

8.	A ball is tied to a string and rotated at a uniform speed in a vertical plane. The diagram shows the ball at its lowest position. Which arrow shows the direction of the net force acting on the ball?
		
(Total 1 mark)

9.	A car moves from X to Y along a semicircular path. The radius of the path is 250 m and the time taken to complete the trip is 50 s.
		
	Which of the following correctly shows the magnitude of the average velocity and the magnitude of the average speed?

	Average velocity	Average speed	
A.	10 m s–1	10 m s–1	
B.	10 m s–1	16 m s–1	
C.	16 m s–1	10 m s–1	
D.	16 m s–1	16 m s–1	
(Total 1 mark)

10.	A communications satellite is moving at a constant speed in a circular orbit around Earth. At any given instant in time, the resultant force on the satellite is
A.	zero.
B.	equal to the gravitational force on the satellite.
C.	equal to the vector sum of the gravitational force on the satellite and the centripetal force.
D.	equal to the force exerted by the satellite’s rockets.
(Total 1 mark)

11.	The Moon orbits the Earth.
		
	Which of the following diagrams correctly represents the force(s) acting on the Moon?

(Total 1 mark)

12.	An aircraft is flying at constant speed in a horizontal circle. Which of the following diagrams best illustrates the forces acting on the aircraft in the vertical plane?

(Total 1 mark)

13.	A brick is placed on the surface of a flat horizontal disc as shown in the diagram below. The disc is rotating at constant speed about a vertical axis through its centre. The brick does not move relative to the disc.

	Which of the diagrams below correctly represents the horizontal force or forces acting on the brick?

(Total 1 mark)