Find the speed of a body at the ground when it falls freely from a height of $2\,m$. $(g = 10\,ms^{-2})$

$A$ ball is dropped from a height $h$ above the ground. Neglecting air resistance,its velocity $(v)$ varies with its height $(y)$ above the ground as:

Two stones of different masses are dropped simultaneously from the top of a building. Which of the following statements is true regarding their motion?

$A$ ball projected from the ground vertically upward is at the same height at times $t_1$ and $t_2$. The speed of projection of the ball is [Neglect the effect of air resistance].

$A$ boy throws balls into the air at a regular interval of $2 \, s$. The next ball is thrown when the velocity of the first ball is zero. How high does the ball rise above his hand (in $, m$)? [Take $g = 9.8 \, m/s^2$]

$A$ ball projected up passes the same height $H$ at $2 \,s$ and $10 \,s$. The value of $H$ is [Use $g=9.8 \,m/s^2$]. (in $m$)