A boy standing on the viewing platform of the Qutub Minar. He then throws a ball vertically downwards at $2\text{m/s}$. If the platform is $72\text{m}$ above ground, the speed with which the ball hits the ground in $\left(\text{m/s}\right)$ is

Q. A boy standing on the viewing platform of the Qutub Minar. He then throws a ball vertically downwards at $2\text{m/s}$. If the platform is $72\text{m}$ above ground, the speed with which the ball hits the ground in $\left(\text{m/s}\right)$ is

Q. A boy standing on the viewing platform of the Qutub Minar. He then throws a ball vertically downwards at $2\text{m/s}$. If the platform is $72\text{m}$ above ground, the speed with which the ball hits the ground in $\left(\text{m/s}\right)$ is

Q. A boy is standing on top of a tower of height $85m$ and throws a ball in the vertically upward direction with a certain speed. If $5.25$ seconds later he hears the ball hitting the ground, then the speed with which the boy threw the ball is (take $g=10m/s^2$, the speed of sound in air $=340m/s)$:

Q. A platform is moving upwards with a constant acceleration of $2m{s}^{-2}$. At time $t=0$, a boy standing on the platform throws a ball upwards with a relative speed of $8m{s}^{-1}$. At this instant, platform was at the height of 4 m from the ground and was moving with a speed of $2m{s}^{-1}$.
Take g = 10 m s${}^{-2}$. Find
a. when and where the ball strikes the platform.
b. the maximum height attained by the ball from the ground.
c. the maximum distance of the ball from the platform.