$A$ 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 $, J$)?

$A$ battery lights a bulb. Describe the energy changes involved in the process.

The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?

An object of mass $m$ is moving with a constant velocity $v$. How much work should be done on the object in order to bring the object to rest?

Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?

$A$ pair of bullocks exerts a force of $140 \, N$ on a plough. The field being ploughed is $15 \, m$ long. How much work is done in ploughing the length of the field (in $, J$)?