If the height of a projectile at a time of 2 s from the beginning of motion is 60 m , then the time of flight of the projectile is

(Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

The angle of projection of a projectile whose path is shown in the given figure is

If the equation of motion of a projectile is $y=A x-B x^2$, then the ratio of the maximum height reached and the range of the projectile is

The height of ceiling in an auditorium is 30 m . A ball is thrown with a speed of $30 \mathrm{~ms}^{-1}$ from the entrance such that it just moves very near to the ceiling without touching it and then it reaches the ground at the end of the auditorium. Then, the length of auditorium is [Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ ]