What would be the amount of work done on an object by a force,if the displacement of the object is zero?

Calculate the power of an engine required to lift $10^{5} \text{ kg}$ of coal per hour from a mine $360 \text{ m}$ deep. [Take $g = 10 \text{ m s}^{-2}$]

An object of mass $10 \ kg$ is made to fall freely from a height of $10 \ m$. Complete the table:

Height of object $(m)$	$PE$ $(J)$	$KE$ $(J)$	Mechanical Energy $(J)$
$10$	...	...	...
$8$	...	...	...
$5$	...	...	...
Just above ground	...	...	...

Hence,state the law of conservation of energy.

Justify,giving proper reasoning,whether the work done in the following case is positive or negative: Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.

Give the formula for calculating work done. What is the $SI$ unit of work?

When a body falls freely towards the earth,then its total energy