Question

A block is placed on a rough wedge fixed on a lift as shown in figure. A string is also attached with the block.The whole system moves upwards. Block does not lose contact with wedge on the block. Match the following two columns regarding the work done.

Answer 1

Friction Force $=0$, as tension will serve that purpose
Angle between $N$ and $S$ or between $T$ and $S$ is acute
$\therefore W_T\text{and}{W}_N$ are positive. Angle between $S$ and $mg$ is $180$.
Therefore, $W_{m}g$ is negative.