The time of flight of an object projected with speed $20 \,ms ^{-1}$ at an angle $30^{\circ}$ with the horizontal, is .... $s$

If the range of a gun which fires a shell with muzzle speed $V$ is $R$, then the angle of elevation of the gun is

The projectile motion of a particle of mass $5\, g$ is shown in the figure.

The initial velocity of the particle is $5 \sqrt{2}\, ms ^{-1}$ and the air resistance is assumed to be negligible. The magnitude of the change in momentum between the points $A$ and $B$ is $x \times 10^{-2}\, kgms ^{-1} .$ The value of $x ,$ to the nearest integer, is ...... .

A ball is projected with kinetic energy $E$ at an angle of ${45^o}$ to the horizontal. At the highest point during its flight, its kinetic energy will be

Shots are fired from the top of a tower and from its bottom simultaneously at angles $30^o$ and $60^o$ as shown. If horizontal distance of the point of collision is at a distance $'a'$ from the tower then height of tower $h$ is :

A projectile is thrown in the upward direction making an angle of $60^o $ with the horizontal direction with a velocity of $147\ ms^{-1}$ . Then the time after which its inclination with the horizontal is $45^o $ , is    ......... $\sec$