State the meaning of centripetal acceleration.
An unpowered toy car travels freely along a smooth track that begins horizontally. The track includes a vertical circular loop, and the car moves round it as shown in Fig. 1.1. The car has a mass of $230\,\text{g}$ and the loop has a diameter of $62\,\text{cm}$. Take the resistive forces on the car to be negligible.
State how the magnitude of the centripetal acceleration of the car changes as it travels round the loop from X to Y.
Explain why, if the car stays in contact with the track, the centripetal acceleration of the car at point Y must be greater than $9.8\,\text{m s}^{-2}$.
The car in (b) is launched with an initial speed of $3.8\,\text{m s}^{-1}$. Determine whether the car is in contact with the track at point $Y$. Show your working.
Suggest, with a reason but without calculation, whether your conclusion in (c) would be different for a car of mass $460\,\text{g}$ travelling with the same initial speed.