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 $, J$)

Calculate the kinetic energy of a body of mass $2 \, kg$ moving with a velocity of $0.1 \, m s^{-1}$. (in $, J$)

We wind our watch once a day,what happens to the energy?

An automobile engine propels a $1000 \,kg$ car $(A)$ along a levelled road at a speed of $36 \,km \,h^{-1}$. Find the power if the opposing frictional force is $100 \,N$. Now,suppose after travelling a distance of $200 \,m$,this car collides with another stationary car $(B)$ of the same mass and comes to rest. Let its engine also stop at the same time. Now car $(B)$ starts moving on the same level road without its engine started. Find the speed of the car $(B)$ just after the collision.

$A$ man rowing a boat upstream is at rest with respect to the shore. Is he doing work?

$(a)$ $A$ person is holding a bucket of water by applying a vertical force of $100 \, N$. He first moves a horizontal distance of $5 \, m$ and then climbs up through stairs a vertical distance of $10 \, m$. Calculate the total work done by the person on the bucket.
$(b)$ Establish the relationship between kinetic energy and momentum of a body.