
Work done $\mathrm{BC}=-\left(4000\right.$ Dyne $\left./ \mathrm{cm}^2\right) \times 4 \mathrm{~m}^3$
Total work done $=2000$ Dyne $/ \mathrm{cm}^2 \times 4 \mathrm{~m}^3$
$=2 \times 10^3 $ $\times \frac{1}{10^5} \frac{\mathrm{N}}{\mathrm{cm}^2} \times 4 \mathrm{~m}^3 $
$ =2 \times 10^{-2} \times \frac{\mathrm{N}}{10^{-4} \mathrm{~m}^2} \times 4 \mathrm{~m}^3 $
$ =2 \times 10^2 \times 4 \mathrm{Nm}=800 \mathrm{~J}$


