NCERT Solutions for Chapter: Laws of Motion, Exercise 3: VSA

 A person driving a car suddenly applies the brakes on seeing a child on the road ahead. If he is not wearing the seat belt, he falls forward and hits his head against the steering wheel. Why?

 The velocity of a body of mass $2 \mathrm{kg}$ as a function of $t$ is given by $\overrightarrow{v}\left(t\right)=2t\hat{i}+t^2\hat{j}$. Find the momentum and the force acting on it, at time $t=2 \mathrm{s}$

 A block placed on a rough horizontal surface is pulled by a horizontal force $\mathrm{F}$. Let $f$ be the force applied by the rough surface on the block. Plot a graph of $f$ versus $F$.

Why are porcelain objects wrapped in paper or straw before packing for transportation?

 Why does a child feel more pain when she/he falls down on a hard cement floor than when she/he falls on the soft muddy ground in the garden?

A woman throws an object of mass $500 \mathrm{g}$ with speed of $25 {\text{m s}}^{-1}$.

What is the impulse imparted to the objects?

A woman throws an object of mass $500 \mathrm{g}$ with speed of $25 {\text{m s}}^{-1}$.

If the object hits a wall and rebounds with half the original speed, what is the change in momentum of the object?

 Why are mountain roads generally made winding upwards rather than going straight up?