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A body of mass $2 \mathrm{~kg}$ is moving with a constant acceleration of $(2 \hat{i}+3 \hat{j}-\hat{k}) \mathrm{ms}^{-2}$. If the displacement made by the body is $(3 \hat{i}-\hat{j}+2 \hat{k}) \mathrm{m}$ then the work done is
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$2 \mathrm{~J}$
$\begin{aligned} & \text { Mass of body, } m=2 \mathrm{~kg} \\ & \text { acceleration, } a=2 \hat{i}+3 \hat{j}-\hat{k} \\ & \text { displacement, } \vec{s}=3 \hat{i}-\hat{j}+2 \hat{k} \\ & \text { work done, } W=F \cdot S \\ & =m \vec{a} \cdot \vec{s} \\ & =2(2 \hat{i}+3 \hat{j}-\hat{k})(3 \hat{i}-\hat{j}+2 \hat{k}) \\ & =2[6-3-2]=2 J\end{aligned}$
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