#### Answer

$P_o=4.36hp$

#### Work Step by Step

We can determine the required power output as follows:
We know that
$2v_p+v_M=0$
$\implies v_M=-2v_p=-2(-4)=8ft/s$
Now $P_o=Fv$
We plug in the known values to obtain:
$P_o=(\frac{600}{2})(8)$
$\implies P_o=2400lb\cdot ft/s=\frac{2400}{550}hp=4.36hp$