Two projectiles, one fired from surface of earth with velocity $10 \,m/s$ and other fired  from the surface of another planet with initial speed $5\, m/s$ trace identical trajectories.  The value of acceleration due to the gravity on the planet is   ......... $m/s^2$

A person can throw a ball upto a maximum range of $100 \,m$. How high above the ground he can throw the same ball?

A cricketer can throw a ball to a maximum horizontal distance of $100 \,m$. With the same effort, he throws the ball vertically upwards. The maximum height attained by the ball is  ......... $m$

A particle is projected in air at some angle to the horizontal, moves along parabola as shown in figure where $x$ and $y$ indicate horizontal and vertical directions respectively. Shown in the diagram, direction of velocity and acceleration at points $A, \,B$ and $C$.

Galileo writes that for angles of projection of a projectile at angles $(45 + \theta )$ and $(45 - \theta )$, the horizontal ranges described by the projectile are in the ratio of (if $\theta \le 45)$

A ball is thrown from a point with a speed ${v_o}$ at an angle of projection $\theta $. From the same point and at the same instant a person starts running with a constant speed ${v_o}/2$ to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection