1. The problem statement, all variables and given/known data A 500 kg ox runs and speeds up by 3 m/s2, but is held back by a 120 kg plow that is attached to its back. Assuming the coefficient of static friction between the horse's hooves and the soil is 0.73, what is the magnitude of the static friction force the soil exerts on the horse's hooves (not maximum static friction) which explains the horse's acceleration? 2. Relevant equations Fsfr ≤ μFN FN=mg 3. The attempt at a solution FN = 500(9.8) = 4900 N Fsfr ≤ 0.73(4900) max static friction = 3600 N ^I got up until here. I'm confused about finding the magnitude of the static friction force...do I have to find the force the plow exerts on the horse and subtract that from 3600 N? If so, how would I find that force?