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 $J$)

$A$ body constrained to move along the $y$-axis is subjected to a constant force $\vec{F} = -\hat{i} + 2\hat{j} + 3\hat{k} \text{ N}$. The work done by this force in moving the body a distance of $4 \text{ m}$ along the $y$-axis is ............... $J$.

$A$ body moves a distance of $10 \ m$ along a straight line under the action of a force of $5 \ N$. If the work done in this process is $25 \ J$,what is the angle between the force and the displacement in degrees?

If force and displacement of a particle in the direction of force are doubled,the work done would be:

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

$A$ particle is made to move from the origin in three spells of equal distances,first along the $x$-axis,second parallel to the $y$-axis,and third parallel to the $z$-axis. One of the forces acting on it has a constant magnitude of $50 \ N$ and always acts along the direction of motion. Work done by this force in the three spells of motion are equal,and the total work done in all three spells is $300 \ J$. The final coordinates of the particle will be: