The trajectory of a projectile is

$A$ boy standing on a moving truck throws a projectile such that he is able to catch it back after the truck has moved $100 \,m$. If the truck is moving horizontally along a straight line with a constant speed $30 \,m/s$, at what speed (relative to the truck) must the projectile be thrown? (Assume $g = 10 \,m/s^2$)

The range of a projectile for a given initial velocity is maximum when the angle of projection is $45^\circ$. The range will be minimum,if the angle of projection is ......... $^\circ$.

On which factors does the value of the range of a projectile depend? On which factors does the maximum value of the range depend?

$A$ body of mass $1 \, kg$ is projected from the ground at an angle of $30^{\circ}$ with the horizontal on level ground at a speed of $50 \, m/s$. The magnitude of the change in momentum of the body during its entire flight is ....... $kg \cdot m/s$ $(g = 10 \, m/s^2)$.

$A$ stone is just released from the window of a train moving along a horizontal straight track. The stone will hit the ground following: