Answer
49.87 s
Work Step by Step
Here we use equation 14.7 $U=\frac{3}{2}nRT$ to find the time.
We can write,
$$time\space (t)=\frac{Energy}{Power}=\frac{U}{Power}=\frac{\frac{3}{2}nRT}{Power}$$
Substituting $PV=nRT$ from the ideal gas law into the above equation yields,
$t=\frac{3PV}{2Power}$; Let's plug known values into this equation.
$t=\frac{3(6.2\times10^{5}Pa)(0.01\space m^{3})}{2(0.25\space hp)(\frac{746\space W}{1\space hp})}=49.87\space s$
