A stunt cyclist drives his motorcycle around the loop-the-loop arrangement, with a radius of 14.7m. This time, however, weA????1re going to allow a margin of safety: instead of feeling weightless at the top, the cyclist feels himself pushed into the seat with a force equal to his own weight, so his speed must be greater than the bare minimum needed to stay in contact with the surface. Remember that the acceleration of gravity is in the same direction as the centripetal acceleration at the top of the loop, and in the opposite direction at the bottom. Remember also that the normal force acting upon him is the force he actually feels.

1. How fast is the cyclist moving at the top of the loop?

2. He then drives down the loop, with only gravity acting to increase his kinetic energy (no additional power from the engine) and no frictional losses. How fast is he moving at the bottom of the loop?

3. Find his centripetal acceleration at the bottom of the loop.

4. The mass of the rider is 75 kg. Find the normal force acting on the rider at the bottom of the loop.