Question

A force of 315N is applied horizontally to a crate in order to displace the crate 35.0m 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 14 percent of the crate's initial internal energy. Calculate the initial internal energy of the crate. (disregard the work done on the floor, assume that all work goes into the crate)

Answer 1

Let:

$$\begin{array}{l} F = 315N \\ S = 35m \\ A = 14\% E0 \\ E0 = ? \\ \end{array}$$ $$A = E0 * 0.14$$ $$E0 = \frac{A}{0.14} = \frac{F + S}{0.14}$$ $$E0 = \frac{315 + 35}{0.14} = 78750J$$

Answer: 78750J