Answer
(a) $-7.2KJ$
(b) $28m$
(c) $260N$
Work Step by Step
(a) We can find the required work done as
$W=\Delta K.E=\frac{1}{2}mv_f^2-\frac{1}{2}mv_i^2$
We plug in the known values to obtain:
$W=0-\frac{1}{2}(65+8.8)(14)^2$
$W=-7200J$
$W=-7.2KJ$
(b) We can find the required distance as follows:
$\Delta x=\frac{1}{2}(v_{\circ}+v)t$
We plug in the known values to obtain:
$\Delta x=\frac{1}{2}(14+0)(4.0)$
$\Delta x=28m$
(c) We can find the required force as
$F=\frac{W}{\delta x}$
We plug in the known values to obtain:
$F=\frac{7200}{28}$
$F=260N$
