A force of 310 N is applied horizontally to a crate in order to displace the crate 45.0 m across a level floor at a constant velocity.

A force of 310 N is applied horizontally to a crate in order to displace the crate 45.0 m across a level floor at a constant velocity. As a result of this work, the crate's internal energy is increased by an amount equal to 12 percent of the crate's initial internal energy. Calculate the initial internal energy of the crate. (Disregard the work done on the floor, and assume that all work goes into the crate.)