If two stones are projected at angle $\theta$ and $\left(90^{\circ}-\theta\right)$ respectively with horizontal with a speed of $20 \mathrm{~ms}^{-1}$. If second stone rises 10 m higher than the first stone then, the angle of projection $\theta$ is (acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

An object of mas $m$ is projected with an initial velocity $u$ with angle of $\theta$ with the horizontal. The average power delivered by gravity in reaching the highest point

A projectile can have the same range $R$ for two angles of projection. Their initial velocities are same. If $T_1$ and $T_2$ are times of flight in two cases, then the product of two times of flight is directly proportional to

A 2 kg ball thrown vertically upward and another 3 kg ball projected with certain angle $\left(\theta \neq 90^{\circ}\right)$ both will have same time of flight, then this ratio of their maximum heights is