Hey Guys, I'm having a lot of problems trying to answer a word problem and could use some help thanks.

....its a long one so sorry

A point on the outside of the axle of a truck has a circular motion that can be modelled by a since curve.

If you measure distance from the axle's centre to the bottom of the truck, that distance remains constant as long as the truck is on a level road. If the truck goes over a bump, the springs absorb the shock but the truck bounces for a while.

A truck is moving so that the axle, which is 6cm in diameter, rotates at 1 rotation per second. As the truck hits a bump, the spring depresses by 20cm and then continues to depress by 80% of the previous bounce as it bounces every half-second.

If the middle of the axle is 30cm from the bottom of the truck, construct a graph and equation illustrating the distance from a point on the outside of the axle to the bottom of the truck.

The question is only worth 2 marks but I would still like to try to get it....you don't need to make the graph but helping with the equation would be nice....

Thanks