A stone is dropped from the top of a tower of height $h$. After $1 \mathrm{second}$ another stone is dropped from the balcony $20 \mathrm{m}$ below the top of the tower. Both reach the bottom simultaneously. What is the value of $h$?  (take $g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

Two particles $A$ and $B$ are projected from a building. $A$ is projected with speed $2V$ making an angle $30°$ with horizontal and $B$ with speed $V$ making an angle $60°$ with horizontal. Which particle will hit the ground earlier

A ball was thrown from height $H$ and the ball hit the floor with velocity $10\left(\hat{\mathrm{i}}–\hat{\mathrm{j}}\right)$ after $1.5 \sec$ of its projection. Find the initial speed of the ball.

A ball was thrown from height $H$ and the ball hit the floor with velocity $10\left(\hat{\mathrm{i}}–\hat{\mathrm{j}}\right)$ after $1.5 \sec$ of its projection. Find the angle of projection $\mathrm{\theta }$

A ball was thrown from height $H$ and the ball hit the floor with velocity $10\left(\hat{\mathrm{i}}–\hat{\mathrm{j}}\right)$ after $1.5 \sec$ of its projection. Find the height $H$.