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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

In uniform circular motion, which of the following is incorrect?

  • Magnitude of the velocity is constant

  • The direction of the velocity is constant

  • The centripetal force is towards the centre of the circle

  • The centripetal force is at 90 o to the velocity

Choose your answer
  

Question 2

Marks: 1

A child whirls a conker on a string around their head. The conker moves with uniform circular motion. The linear speed of the conker is 5 m s−1 and the radius of the circle is 0.5 m. 

Calculate the angular speed of the conker.

  • 2.5 rad s−1

  • 0.5 rad s−1

  • 10 rad s−1

  • 5 rad s−1

Choose your answer
  

Question 3

Marks: 1

What is an angular displacement of pi over 6 rad in degrees?

  • 180 o

  • 60 o

  • 45 o

  • 30 o

Choose your answer
  

Question 4

Marks: 1

The linear speed of a motorcycle of mass 50 kg on a circular race track is 10 m s−1. The radius of the race track is 500 m.

What is the centripetal force acting on the motorcycle?

  • 10 N

  • 50 N

  • 150 N

  • 100 N

Choose your answer
  
Key Concepts
Centripetal Force

Question 5

Marks: 1

An athletic hammer consists of a heavy metal ball on the end of a steel wire which is rotated around an athlete's head before being released.

The angular speed obtained by a training hammer thrown in a competition is 2 rad s−1. The combined length of the steel rope and the athlete's arms is 2 m.

What is the centripetal acceleration of the hammer?

  • 2 m s−2

  • 4 m s−2

  • 6 m s−2

  • 8 m s−2

Choose your answer
  

Question 6

Marks: 1

A man is running along a circular path with an angular velocity of 0.05 rad s−1. His linear velocity is 2.5 m s−1.

What is the radius of the path?

  • 20 m

  • 30 m

  • 40 m

  • 50 m

Choose your answer
  

Question 7

Marks: 1

A mass is swung on a string in a circle of radius r.

6-1-circular-motion--q7-question-sl-easy-mcq-phy

The string breaks and the mass continues to move.

Which line in the table below describes the motion of the mass in the horizontal and vertical dimensions?

 

Horizontal

Vertical

A.

Continues in a circle of radius r

No vertical motion

B.

Moves in a circle of radius > r

Moves at a constant speed downwards

C.

No horizontal motion

Decelerates downwards

D.

Moves in a straight line at 90 ° to r

Accelerates downwards

    Choose your answer
      

    Question 8

    Marks: 1

    A ball attached to a string rotates in a gravitational field with a constant time period in a vertical plane. The forces acting on the mass are tension, T and weight, W.

    6-1-circular-motion-q8-question-sl-easy-mcq-phy

    What is an expression for the magnitude of the tension in the string at the top of the circle?

    • fraction numerator m v squared over denominator r end fraction minus m g

    • T

    • mg

    • fraction numerator m v squared over denominator r end fraction plus m g

    Choose your answer
      

    Question 9

    Marks: 1

    A satellite moves in a uniform circular orbit around the Earth in a clockwise direction. 

    Which diagram correctly shows the direction of the velocity v and acceleration a of the satellite at the position shown?

    6-1-circular-motion-q9-question-sl-easy-mcq-phy

      Choose your answer
        

      Question 10

      Marks: 1

      What is the force acting on an object rotating with constant speed v in a circle of radius r?

      • fraction numerator m v squared over denominator r end fractiontowards the centre of the circle

      • v squared over raway from the centre of the circle

      • fraction numerator m v squared over denominator r end fractionalong a tangent to the circle

      • No force acts on the object

      Choose your answer
        
      Key Concepts
      Centripetal Force