$A$ box of mass $10 \, kg$ is placed at point $A$ on a horizontal surface. It is moved to point $B$,which is at a distance of $2 \, m$ from $A$. If the line joining $A$ and $B$ is horizontal,find the work done by the gravitational force on the box. Justify your answer. $(g = 10 \, m s^{-2})$ (in $, J$)

Seema tried to push a heavy rock of $100 \, kg$ for $200 \, s$ but could not move it. Find the work done by Seema at the end of $200 \, s$. (in $, J$)

Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term 'work'.
$1$. Suma is swimming in a pond.
$2$. $A$ donkey is carrying a load on its back.
$3$. $A$ windmill is lifting water from a well.
$4$. $A$ green plant is carrying out photosynthesis.
$5$. An engine is pulling a train.
$6$. Food grains are getting dried in the sun.
$7$. $A$ sailboat is moving due to wind energy.

$A$ person continues to push a heavy mass for some time but fails to move it. What is the work done by him?

One joule of work is said to be done when:

$A$ force of $7\, N$ acts on an object. The displacement is $8\, m$ in the direction of the force. What is the work done in this case (in $, J$)?