Answer
The work done by the crate is approximately $1115\text{ foot-pounds}$.
Work Step by Step
The amount of work done by a force $\mathbf{F}$ on an object from a point A to the point B is denoted by $W=\mathbf{F}\cdot \overrightarrow{AB}$.
That is $W=\left\| \mathbf{F} \right\|\overrightarrow{\left\| AB \right\|}\cos \theta $ ;
Where $\theta $ is the angle between the force and the direction of the motion.
In the given case, the distance between the crate and the level of floor is 50 feet.
$\begin{align}
& \left\| \overrightarrow{AB} \right\|=50 \\
& \theta =42{}^\circ
\end{align}$
And, the magnitude of force $\left\| \mathbf{F} \right\|=30$.
Therefore, the amount of work done will be calculated as below:
$\begin{align}
& W=\left\| \mathbf{F} \right\|\overrightarrow{\left\| AB \right\|}\cos \theta \\
& =\left( 30 \right)\left( 50 \right)\cos 42{}^\circ \\
& =1500\left( 0.743144825 \right) \\
& =1114.71
\end{align}$
This implies $W\approx 1115$.
So, work done by the crate is approximately $1115\text{ foot-pounds}$.
Hence, the amount of work done by the crate is approximately $1115\text{ foot-pounds}$.
