Bicycle with a rider applying weight to on pedal. Draw as free bodies in equilibrium. There are different situations.
The Attempt at a Solution
So I am working on part a).
1. I believe it is only referring to just the pedal, chain, and the two smaller circles of the (sprocket??).
2. Assuming that is correct to balance the 800N there would need to be an opposing force, is this the torque that is created on the smaller rear circle or is it just as simple as an opposing force in the left side of the pedal?