If a stone projected from the ground takes $4 \, s$ to reach the topmost point of its trajectory,then the time of flight is .......... $s$.

In the projectile motion of a particle on a level ground,which of the following remains constant with reference to time and position?

$A$ missile is fired for maximum range at your town from a place $100 \, km$ away from you. If the missile is first detected at its half-way point,how much warning time will you have? (Take $g = 10 \, m/s^2$)

$A$ cricketer hits a ball with a velocity $25\,m/s$ at $60^\circ$ above the horizontal. How far above the ground does it pass over a fielder $50\,m$ from the bat (in $,m$)? (Assume the ball is struck very close to the ground and $g = 9.8\,m/s^2$)

For a given angle of the projectile,if the initial velocity is doubled,the range of the projectile becomes:

$A$ body is projected at an angle of $30^{\circ}$ with the horizontal with momentum $p$. At its highest point,the magnitude of the momentum is