39. A 12-kg crate is pulled along a horizontal floor by a force of 60 N which is applied at an angle of 280 above the horizontal. The coefficient of kinetic friction between the crate and the floor is 0.32. 60 N 280 12 kg a) Find the magnitude of the normal force acting on the crate. b) Find the friction acting on the crate. c) Find the acceleration of the crate