Crate is being pushed a constant velocity. What forces are being used?

Since the crate is moving at constant velocity the net force on the crate is zero. Since the crate is moving we are referring to the coefficient of dynamic friction. R is the reaction and is equal to the weight of the block mg. The effort is now doubled so the forces on the block are not balance

Awoodchuck would chuck all the wood he could chuck if a woodchuck could chuck wood.

This is kenetic energy.