Find the energy in $kWh$ consumed in $10$ hours by four devices of power $500\, W$ each. (in $kWh$)

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?

Define average power.

What is the kinetic energy of an object?

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

$A$ certain household has consumed $250$ units of energy during a month. How much energy is this in joules?