A stone is projected from the ground with velocity $50 \,m/s$ at an angle of ${30^o}$. It crosses a wall after $3$ sec. How far beyond the wall the stone will strike the ground ..........  $m$ $(g = 10\,m/{\sec ^2})$

A ball is projected from the ground with a speed $15 \,ms ^{-1}$ at an angle $\theta$ with horizontal so that its range and maximum height are equal, then $tan\,\theta$ will be equal to 

A projectile crosses two walls of equal height $H$ symmetrically as shown The angle of projection of the projectile is

Derive the formula for Range of a projectile $(R)$. Derive the formula for maximum projectile.

A ball is thrown from a roof top at an angle of $45^o$ above the horizontal. It hits the ground a few seconds later. At what point during its motion, does the ball have $(a)$ greatest speed $(b)$ smallest speed $(c)$ greatest acceleration - Explain.

The horizontal range of a projectile is $4\sqrt 3 $ times its maximum height. Its angle of projection will be    ......... $^o$