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Circular Motion - Multiple choice

Q11. A fairground roundabout makes nine revolutions in one minute.

What is the angular speed of the roundabout?

A
 0.15 rad s–1
B
 0.34 rad s–1
C
 0.94 rad s–1
D
 2.1 rad s–1

 

Q12. The figure shows a smooth thin tube T through which passes a string with masses m and M attached to its ends.

Initially the tube is moved so that the mass, m, travels in a horizontal circle of constant radius r, at constant speed, v.

Which one of the following expressions is equal to M?

A
mv2/2r
B
mv2rg
C
mv2g/r
D
mv2/rg

 

Q13. What is the angular speed of a point on the Earth's equator?

A 7.3 × 10–5 rad s–1
B 4.2 × 10–3 rad s–1
C 2.6 × 10–1 rad s–1
D 15 rad s–1

 

Q14. For a particle moving in a circle with uniform speed, which one of the following statements is correct?

A

The displacement of the particle is in the direction of the force.

B

The force on the particle is in the same direction as the direction of motion of the particle.

C

The momentum of the particle is constant.
D

The kinetic energy of the particle is constant.

 

Q15. An object moving at constant speed in a circle experiences a force that is

A in the direction of motion.
B outwards and at right angles to the direction of motion.
C inwards and at right angles to the direction of motion.
D opposite to the direction of motion.

 

Q16. A ball of mass m, which is fixed to the end of a light string of length l, is released from rest at X. It swings in a circular path, passing through the lowest point Y at speed v.

If the tension in the string at Y is T, which one of the following equations represents a correct application of Newton's laws of motion to the ball at Y?

A
B
C
D

 

Q17. A disc of diameter D is turning at a steady angular speed at frequency f about an axis through its centre.

What is the centripetal force on a small object O of mass m on the perimeter of the disc?

A
2πmfD
B
2πmf2D
C
2π2mf2D
D
2πmf2D2

 

Q18. What is the angular speed of a car wheel of diameter 0.400 m when the speed of the car is 108 kmh–1 ?

A
175 rad s–1
B
150 rad s–1
C
270 rad s–1
D
540 rad s–1

 

 

Q19. A bob of mass 0.50 kg is suspended from the end of a piece of string 0.45 m long.

The bob is rotated in a vertical circle at a constant rate of 120 revolutions per minute.

What is the tension in the string when the bob is at the bottom of the circle?

 

A
5.8 N
B
31 N
C
36 N
D
40 N