This diagram shows part of the track of a roller-coaster ride in which a truck loops the loop. When the truck is at the position shown, there is no reaction force between the wheels of the truck and the track. The diameter of the loop in the track is $8.0\mathrm{m}$.

Explain what provides the centripetal force to keep the truck moving in a circle.

This diagram shows part of the track of a roller-coaster ride in which a truck loops the loop. When the truck is at the position shown, there is no reaction force between the wheels of the truck and the track. The diameter of the loop in the track is $8.0\mathrm{m}$.

Given that the acceleration due to gravity g is 9.8m s^-2, calculate the speed of the truck.

This diagram shows a toy of mass $60 \mathrm{g}$ placed on the edge of a rotating turntable.

The radius of the turntable is $15.0\mathrm{cm}$. The turntable rotates, making $20$ revolutions every minute. Calculate the resultant force acting on the toy.

This diagram shows a toy of mass $60 \mathrm{g}$ placed on the edge of a rotating turntable.

Explain why the toy falls off when the speed of the turntable is increased.

One end of a string is secured to the ceiling and a metal ball of mass $50 \mathrm{g}$ is tied to its other end. The ball is initially at rest in the vertical position. The ball is raised through a vertical height of $70 \mathrm{cm}$, as shown. The ball is then released. It describes a circular arc as it passes through the vertical position.

The length of the string is $1.50 \mathrm{m}$. Ignoring the effects of air resistance, determine the speed $v$ of the ball as it passes through the vertical position.

One end of a string is secured to the ceiling and a metal ball of mass $50 \mathrm{g}$ is tied to its other end. The ball is initially at rest in the vertical position. The ball is raised through a vertical height of $70 \mathrm{cm}$, as shown. The ball is then released. It describes a circular arc as it passes through the vertical position.

The length of the string is $1.50 \mathrm{m}$. Calculate the tension Tin the string when the string is vertical.

One end of a string is secured to the ceiling and a metal ball of mass $50 \mathrm{g}$ is tied to its other end. The ball is initially at rest in the vertical position. The ball is raised through a vertical height of $70 \mathrm{cm}$, as shown. The ball is then released. It describes a circular arc as it passes through the vertical position.

The length of the string is $1.50 \mathrm{m}$. Explain why your answer to b is not equal to the weight of the ball.

A car is travelling round a bend when it hits a patch of oil. The car slides off the road onto the grass verge. Explain, using your understanding of circular motion, why the car came off the road.

This diagram shows an aeroplane banking to make a horizontal tum. The aeroplane is travelling at a speed of $75 {\mathrm{ms}}^{-1}$ and the radius of the turning circle is $800 \mathrm{m}$.

Copy the diagram. On your copy, draw and label the forces acting on the aeroplane.