You have to move your 900N couch before a delivery company drops off your new one. Unfortunately your roommate is passed out on it. The coefficient of friction between the couch and floor is 0.40. It takes 730N of force to get the couch moving.
a) How much does your roommate weigh?
b) After you get the couch moving it only takes 400 N to keep it moving at a constant speed, what is the coefficient of kinetic friction?