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DP IB Physics: HL

Topic Questions

Home / IB / Physics: HL / DP / Topic Questions / 6. Circular Motion & Gravitation / 6.1 Circular Motion / Multiple Choice


6.1 Circular Motion

Question 1

Marks: 1

A particle of mass m moves in a circle of radius r at uniform speed, taking time T for each revolution. What is the kinetic energy of the particle?

  • 2 m r pi f squared

  • m r squared pi squared f squared

  • 2 m r squared pi squared f squared

  • 4 m r squared pi squared f squared

Choose your answer
  

Question 2

Marks: 1

A 0.05 kg ball is attached to an inextensible string and whirled overhead such that it rotates in a horizontal circle.

What is the centripetal force on the ball if the string is 0.1 m long and the ball has a time period of  pi over 10s?

  • 1.0 N 

  • 0.1 N

  • 8.0 N

  • 2.0 N

Choose your answer
  
Key Concepts
Centripetal Force

Question 3

Marks: 1

A horizontal disc rotates uniformly at a constant angular velocity about a central axis normal to the plane of the disc.

q13_circular-motion_ib-sl-physics-mcq

Point X is on a distance 3L from the centre of the disc. Point Y is a distance L from the centre of the disc. Point Y has a linear speed v and a centripetal acceleration a.

What is the linear speed and centripetal acceleration of point X?

 

Linear Speed of X

Acceleration of X

A.

3v

a

B.

v

a

C.

3v

3a

D.

2v

2a

    Choose your answer
      

    Question 4

    Marks: 1

    A girl of mass 50 kg is standing on a roundabout 100 cm from the centre. The force of friction on the girl is 600 N. What is the time period if the roundabout is rotating uniformly?

    • square root of fraction numerator pi blank over denominator 6 end fraction end root

    • square root of fraction numerator 2 blank over denominator 3 end fraction end rootπ 

    • 1 thirdπ2 

    • square root of fraction numerator 1 blank over denominator 3 end fraction end rootπ 

    Choose your answer
      

    Question 5

    Marks: 1

    A spinning top makes twenty revolutions in five minutes in a clockwise direction.

    What is the angular velocity of the spinning top?

    • fraction numerator 2 pi over denominator 15 end fraction

    • pi over 150

    • 10π

    • 1 over 15

    Choose your answer
      

    Question 6

    Marks: 1

    A body moves in a circle with increasing angular velocity. At times t, the angles θ swept out by the body added cumulatively from the same reference point and its angular velocities ω are as follows:

    t / s

    θ / rad

    ω / rad s–1

    5

    15

    25

    35

    2

    16

    42

    80

    0.4

    2.4

    4.4

    6.4

    The angular acceleration of the body:

    • is constant at 0.2 rad s–2

    • gradually decreases and is 6.25 rad s–2 when t = 15 s

    • is constant at 0.4 rad s–2

    • increases at a constant rate and is 0.2 rad s–2 when t = 15 s

    Choose your answer
      

    Question 7

    Marks: 1

    A hammer thrower rotates a ball on a string in a circular path gradually increasing its angular velocity with each rotation. 

    q17_circular-motion_ib-sl-physics-mcq

    When the hammer releases the ball, the subsequent path taken by the ball is

    • a vertical circle

    • a parabola in a horizontal plane

    • a parabola in a vertical plane

    • a straight line along a radius of the circle

    Choose your answer
      

    Question 8

    Marks: 1

    An object at the end of a steel rod rotates in a vertical circle at a constant angular velocity. Which of the following statements correctly describes the tension in the rod?

    • it is greatest when the object is halfway up the circle

    • it is greatest when the object is at the bottom of the circle

    • it is unchanged throughout the motion

    • it is greatest when the object is at the top of the circle

    Choose your answer
      

    Question 9

    Marks: 1

    For a particle moving in a circle with uniform speed, which of the following statements is incorrect?

    • The speed of the particle is constant

    • The acceleration of the particle is perpendicular to its direction of motion

    • The momentum of the particle is constant

    • The particle is accelerating

    Choose your answer
      
    Key Concepts
    Centripetal Force

    Question 10

    Marks: 1

    A satellite X of mass orbits the Earth with a period T and radius r and linear speed v. What will be the orbital period of satellite Y with mass m occupying an orbit with radius r over 2 and speed 2v as X?

    • 2T

    • T

    • T over 2

    • T over 4

    Choose your answer