Question

If a torque of 36 N⋅m about the x axis is required to tighten the nut, determine the required magnitude of the force F that the man's foot must apply on the end of the wrench in order to turn it. Force F lies in a vertical plane.

Answer 1

Torque = F * D = 36 N-m
You need to know the distance (approximately the length of the wrench) D to find the required force.
The longer the distance D, the smaller the force F.