The range of a particle when launched at an angle of ${15^o}$ with the horizontal is $1.5 \,km$. What is the range of the projectile when launched at an angle of ${45^o}$ to the horizontal ........ $km$

In the given figure for a projectile

A ball is projected with kinetic energy $E$, at an angle of $60^{\circ}$ to the horizontal. The kinetic energy of this ball at the highest point of its flight will become.

A boy can throw a stone up to a maximum height of $10\ m$. The maximum horizontal distance that the boy can throw the same stone up to will be ..........  $m$

A very broad elevator is going up vertically with a constant acceleration of $2\,m / s ^2$. At the instant when its velocity is $4\,m / s$ a ball is projected from the floor of the lift with a speed of $4\,m / s$ relative to the floor at an elevation of $30^{\circ}$. The time taken by the ball to return the floor is $..............\,s$ $\left(g=10\,m / s ^2\right)$

A particle is projected vertically upwards from $O$ with velocity $v$ and a second particle is projected at the same instant from $P$ (at a height h above $O$) with velocity $v$ at an angle of projection $\theta$ . The time when the distance between them is minimum is