SECTION-B

When a ball is thrown vertically upwards, it goes through a distance of $19.6 \mathrm{m}$. Find the initial velocity of the ball and the time taken by it to rise to the highest point. (Acceleration due to gravity, $g = 9.8 \mathrm{m}/{\mathrm{s}}^2$)

The hanging bob of a simple pendulum is displaced to one extreme position $B$ and then released. It swings towards the centre position $A$ and then to the other position $C$. In which position does the bob have maximum potential energy? Give reasons for your answer.

The hanging bob of a simple pendulum is displaced to one extreme position $B$ and then released. It swings towards centre position $A$ and then to the other position $C$. In which position does the bob have Maximum kinetic energy? Give reasons for your answer.

Figure X shows a trace of a sound wave produced by a particular tuning fork:

On the graph paper given in figure $\mathrm{Y}$, draw a trace of the sound wave, which has a higher frequency than that shown in Figure $\mathrm{X}$.

Figure $X$ shows a trace of a sound wave produced by a particular tuning fork:

On the graph paper shown in Figure $Y$, draw a trace of the sound wave, which has a larger amplitude than that shown in figure $X$.

Explain why a cricket player moves his hands backward while catching a fast cricket ball.

A $150 \mathrm{g}$ ball travelling at $30 \mathrm{m} {\mathrm{s}}^{-1}$ strikes the palm of a player’s hand and is stopped in $0.06 \mathrm{s}$. Calculate the force exerted by the ball on the hand.

A coin and a piece of paper are dropped simultaneously from the same height. Which of the two will touch the ground first? What will happen if the coin and the piece of paper are dropped in a vacuum? Give reasons for your answer.