OR if you can't help me with that, maybe you can help me with this

A point on the outside of the axle of the trcuk has a circular motion that can be modelled by a sine 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 piece of road. If the truck foes 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 one rps. As the truck hits a bump the spring depresses by 80% of the previous bounce as it bounces every half second.

so unless im mistaken this would be but possibly multiplied? and the equation for the depression thing is something like and the sine formula as but im not sure thats correct

update: and is what im understanding so far, and i would multiply them. I think im doing this right but some verification would be appreciated