When a force of $50 \, N$ is applied to an object,it undergoes a displacement of $10 \, m$ at an angle of $60^\circ$ with the direction of the force. The work done is ......... $J$.

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 $, J$)?

$A$ ship of mass $3 \times 10^7 \, kg$ initially at rest is pulled by a force of $5 \times 10^4 \, N$ through a distance of $3 \, m$. Assuming that the resistance due to water is negligible,the speed of the ship is ........... $m/s$.

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?

$A$ porter lifts a heavy suitcase of mass $80\, \text{kg}$ and at the destination lowers it down by a distance of $80\, \text{cm}$ with a constant velocity. Calculate the work done by the porter in lowering the suitcase. (Take $g = 9.8\, \text{m/s}^2$) (In $\text{J}$)

If work is done by a body against a force,is the work considered positive or negative?