$A$ body of mass $20 \ kg$ is at rest. $A$ force of $5 \ N$ is applied to it. Find the work done in the first second.

$A$ chain of mass $M$ and length $L$ is hanging from the edge of a table such that one-third of its length is hanging off the edge. The work done to pull the hanging part onto the table is:

$A$ body of mass $m$ is moving in a circle of radius $r$ with a constant speed $u$. The force on the body is $mv^2/r$ and is directed towards the centre. What is the work done by this force in moving the body over half the circumference of the circle?

$A$ force of $(5\hat i + 6\hat j - 7\hat k) \, N$ is applied to a body of mass $10 \, kg$,causing it to displace from position $(4\hat i - 2\hat j + 5\hat k) \, m$ to $(8\hat i + 6\hat j - 3\hat k) \, m$. Calculate the work done in $J$.

$A$ body of mass $m$ kg is lifted by a man to a height of one metre in $30\, s$. Another man lifts the same mass to the same height in $60\, s$. The work done by them are in the ratio:

Work done in raising a box depends on