State Newton's first law of motion. Give two examples to illustrate Newton's first law of motion.

On what factor does the inertia of a body depend? Which has more inertia, a cricket ball or a rubber ball of the same size?

Why do the passengers in a bus tend to fall backward when it starts suddenly?

Explain why, a person travelling in a bus falls forward when the bus stops suddenly.

Give reason for the following:

When a hanging carpet is beaten with a stick, the dust particles start coming out of it.

When a tree is shaken, its fruits and leaves fall down. Why?

Explain why, it is dangerous to jump out of a moving bus.

What is the momentum in $\raisebox{1ex}{$\mathrm{kg}.\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right.$ of a $10 \mathrm{kg}$ car travelling at $\left(\mathrm{a}\right) 5 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right., \left(\mathrm{b}\right) 20 \raisebox{1ex}{$\mathrm{cm}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right. \mathrm{and} \left(\mathrm{c}\right) 36 \raisebox{1ex}{$\mathrm{km}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{hr}$}\right.$ ?

Define momentum of a body. On what factors do the momentum of a body depend?