A projectile crosses two walls of equal height $H$ symmetrically as shown The velocity of projection is........ $ms^{-1}$

A ball is projected from ground with a speed of $20\,m / s$ at an angle of $45^{\circ}$ with horizontal. There is a wall of $25\,m$ height at a distance of $10\,m$ from the projection point. The ball will hit the wall at a height of $.........\,m$

The velocity at the maximum height of a projectile is $\frac{\sqrt{3}}{2}$ times its initial velocity of projection $(u)$. Its range on the horizontal plane is .............

Two projectiles, one fired from surface of earth with velocity $10 \,m/s$ and other fired  from the surface of another planet with initial speed $5\, m/s$ trace identical trajectories.  The value of acceleration due to the gravity on the planet is   ......... $m/s^2$

A projectile is fired at an angle of $45^o $ with the horizontal . Elevation angle of the projectile at its highest point as seen from the point of projection, is 

The maximum height attained by a projectile is increased by $10\,\%$ by increasing its speed of projection, without changing the angle of projection. The percentage increases in the horizontal range will be $...........\,\%$