Answer
(a) $4.8W$
(b) $430J$
Work Step by Step
(a) We can find the required power as follows:
$P=Fv$
We plug in the known values to obtain:
$P=(21)(0.23)$
$P=4.8W$
(b) We know that
$P=\frac{W}{t}$
This can be rearranged as:
$W=Pt$
We plug in the known values to obtain:
$W=(4.8)(1.5\times 60)$
$W=430J$