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 ..... $J$.

$A$ force $\vec{F} = 2\hat{i} + b\hat{j} + \hat{k}$ is applied on a particle and it undergoes a displacement $\vec{S} = \hat{i} - 2\hat{j} - \hat{k}$. What will be the value of $b$,if the work done on the particle is zero?

$A$ particle of mass $m$ is projected with speed $u$ at angle $\theta$ with the horizontal from the ground. The work done by gravity on it during its upward motion is ..........

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

$A$ boy holds a uniform chain of length $2 \, m$ which is kept on a smooth table such that a length of $60 \, cm$ hangs freely from the edge of the table. The total mass of the chain is $4 \, kg$. What is the work done in pulling the entire chain on the table (in $, J$)? (Take $g = 10 \, m/s^2$)

$A$ heavy box of $40\, kg$ is pushed along $20\, m$ by two coolies over a railway platform whose coefficient of friction with the box is $0.4$. The work done by the two coolies is: .................. $J$ (Take $g = 10\, m/s^2$)