When an object is dragged $10 \, m$ along a road,a frictional force of $200 \, N$ acts in the direction opposite to its motion. What is the work done by the frictional force on the object (in $, J$)?

Due to a force of $(6\hat i + 2\hat j) \text{ N}$,the displacement of a body is $(3\hat i - \hat j) \text{ m}$. The work done is ..... $J$.

Given that $W = \vec F \cdot \vec s = 0$ and $F \neq 0, s \neq 0$,then

$A$ block of mass $m$ is kept in an elevator which starts moving downward with an acceleration $a$ as shown in the figure. The block is observed by two observers $A$ and $B$ for a time interval $t_0$. The observer $B$ (who is on the ground) finds that the work done by gravity on the block is:

$A$ $1\text{ kg}$ block subjected to two simultaneous forces $\vec{F}_1 = (2\hat{i} + 3\hat{j} + 4\hat{k})\text{ N}$ and $\vec{F}_2 = (3\hat{i} - \hat{j} - 2\hat{k})\text{ N}$ is moved a distance of $25\text{ m}$ along the $(3\hat{i} - 4\hat{j})$ direction. The work done in this process is . . . . . . $J$.

How much work does a pulling force of $40\, N$ do on a $20\, kg$ box in pulling it $8\, m$ across a smooth floor at a constant speed? The pulling force is directed at $60^{\circ}$ above the horizontal. (Answer in $J$)