$A$ body,acted upon by a force of $50 \, N$,is displaced through a distance of $10 \, m$ in a direction making an angle of $60^\circ$ with the force. The work done by the force is .......... $J$.

$A$ 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 ............... $\text{J}$.

If a person is pushing a box inside a moving train,the work done in the frame of the earth will be: (where $\vec{s}$ is the displacement of the box in the train and $\vec{s}_0$ is the displacement of the train relative to the ground)

Given that a force $\vec{F}$ acts on a body for time $t_1$ and displaces the body by $\vec{d}$. In which of the following cases must the velocity of the body increase?

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

$A$ force $F = (5\hat i + 3\hat j) \, N$ is applied to a particle,which displaces it from its origin to the point $r = (2\hat i - 1\hat j) \, m$. The work done on the particle is: