$A$ force $\vec{F} = 3\hat{i} + c\hat{j} + 2\hat{k}$ acting on a particle causes a displacement $\vec{s} = -4\hat{i} + 2\hat{j} + 3\hat{k}$. If the work done is $6\,J$,then the value of $c$ is:

$A$ ball is dropped from the top of a tower. What is the ratio of the work done by the force of gravity during the $1^{st}$,$2^{nd}$,and $3^{rd}$ seconds?

$A$ man of mass $50 \ kg$ carries a load of mass $20 \ kg$ and climbs $20$ steps,each of height $0.25 \ m$. Calculate the work done in $J$.

$A$ body of mass $10\, kg$ is dropped to the ground from a height of $10\, m$. The work done by the gravitational force is ............. $J$ $(g = 9.8\, m/s^2)$.

$A$ 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:

$A$ particle gets displaced by $\Delta \vec{r} = (2\hat{i} + 3\hat{j} + 4\hat{k}) \text{ m}$ under the action of a force $\vec{F} = (7\hat{i} + 4\hat{j} + 3\hat{k}) \text{ N}$. The change in its kinetic energy is ............... $\text{J}$.