An object is projected from ground with speed $20 \,m / s$ at angle $30^{\circ}$ with horizontal. Its centripetal acceleration one second after the projection is .......... $m / s ^2$ [Take $g=10 \,m / s ^2$ ]

A stone is thrown at an angle $\theta $ to the horizontal reaches a maximum height $H$. Then the time of flight of stone will be

Derive the formula for time taken to achieve maximum, total time of Flight and maximum height attained by a projectile.

Projectiles $A$ and $B$ are thrown at angles of $45^{\circ}$ and $60^{\circ}$ with vertical respectively from top of a $400 \mathrm{~m}$ high tower. If their ranges and times of flight are same, the ratio of their speeds of projection $v_A: v_B$ is :

A ball is projected from ground with a speed of $20\,m / s$ at an angle of $45^{\circ}$ with horizontal. There is a wall of $25\,m$ height at a distance of $10\,m$ from the projection point. The ball will hit the wall at a height of $.........\,m$

A ball of mass $m$ is thrown vertically upward. Another ball of mass $2\,m$ is thrown an angle $\theta$ with the vertical. Both the balls stay in air for the same period of time. The ratio of the heights attained by the two balls respectively is $\frac{1}{x}$. The value of $x$ is $.....$