Answer
(a) $92KJ$
(b) $-62KJ$
Work Step by Step
(a) We know that
$W=P(V_f-V_i)$
$\implies W=P(2V_i-Vi)$
As given, the final volume becomes twice the initial volume
$W=(140)(0.66)$
$W=92KJ$
(b) As $W=P(V_f-V_i)$
$W=P(\frac{1}{3}V_i-V_i)$ As $V_f=\frac{1}{3}V_i$
$W=-\frac{2}{3}PV_i$
We plug in the known values to obtain:
$W=-\frac{2}{3}(140)(0.66)$
$W=-62KJ$
