An object is moving along a straight line path from $P$ to $Q$ under the action of a force $\overrightarrow{F}=\left(4\hat{\mathrm{i}}-3\hat{\mathrm{j}}+2\hat{\mathrm{k}}\right) \mathrm{N}$ If the co-ordinate of $P \& Q$ in metres are $\left(3, 2, -1\right) \& \left(2, -1, 4\right)$ respectively. Then the work done by the force is:

The work done by static friction on an object

A block of mass $m$ is suspended by a light thread from an elevator. The elevator is accelerating upward with uniform acceleration $a.$ The work done by tension on the block during $t$ seconds is $\left(u=0\right):$