Physics - W.E.P. Question with Solution | TestHub

Given,$r_1=\left(3\hat{\mathrm{i}}+2\hat{\mathrm{j}}-6\hat{\mathrm{k}}\right)\mathrm{ }\mathrm{m}$

$r_2=\left(14\hat{\mathrm{i}}+13\hat{\mathrm{j}}+9\hat{\mathrm{k}}\right)\mathrm{ }\mathrm{m}$

$F=\left(4\hat{\mathrm{i}}+\hat{\mathrm{j}}-3\hat{\mathrm{k}}\right)\mathrm{ }\mathrm{N}$

Displacement,$s=r_2-r_1$

$=\left(14\hat{\mathrm{i}}+13\hat{\mathrm{j}}+9\hat{\mathrm{k}}\right)-\left(3\hat{\mathrm{i}}+2\hat{\mathrm{j}}-6\hat{\mathrm{k}}\right)$

or,$s=11\hat{\mathrm{i}}+11\hat{\mathrm{j}}+15\hat{\mathrm{k}}$

$\therefore$Work done,$W=F.s$

$=\left(4\hat{\mathrm{i}}+\hat{\mathrm{j}}-3\hat{\mathrm{k}}\right)\cdot \left(11\hat{\mathrm{i}}+11\hat{\mathrm{j}}+15\hat{\mathrm{k}}\right)$

$=44+11-45$

or$W=10 \mathrm{J}$