6.1 Circular Motion

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.

What is an angular displacement of rad in degrees?

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?

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?

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?

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

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?

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.

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

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?

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