Answer
(a) positive
(b) zero
(c) negative
(d) negative
(e) $11J$
Work Step by Step
(a) We know that the work done by the gas in process AB is positive because the area under this process is positive.
(b) The work done in process BC is zero because it is parallel to the y-axis and hence the change in volume is zero: $\Delta V=0$ and $\Delta W=P\Delta V=0$
(c) We know that the work done in process CD is negative because the change in volume is negative.
(d) Work done in process DA is negative because the change in volume $\Delta V$ is negative.
(e) We know that
$W=\frac{2Q}{5}$
We plug in the known values to obtain:
$W=\frac{2(27J)}{5}$
$\implies W=11J$
