#### Answer

$22,800,00 $ ft- lb

#### Work Step by Step

The force can be found as:
$F(x)= 8 \times 800 [\dfrac{(2) \times 4750-x}{(2) \times (4750)}] =6400 (1- \dfrac{x}{9500} ) lb$
Integrate the integral to calculate the work done area as follows:
Work done,
$W=\int_c^d F(x) dx= \int_{0}^{4750}6400 (1-\dfrac{x}{9500}) dx$
or, $=6400[4750-\dfrac{(4750)^2}{4 \times 4750 }]$
or, $=22,800,00 $ ft- lb