What is the initial velocity of an object falling freely (in $m/s$)?

$A$ balloon rises from rest with a constant acceleration $g/8$. $A$ stone is released from it when it has risen to height $h$. The time taken by the stone to reach the ground is

Draw graphs $a \to t$,$v \to t$,and $x \to t$ for an object falling freely.

$A$ ball is dropped from rest at time $t=0$ from a certain height. $A$ second ball is dropped from the same height at time $t=1 \,s$. At what time $t$, does the distance between the two balls become $10 \,m$ (in $s$)?

The nature of a graph drawn for a freely falling body with time on the $x$-axis and speed on the $y$-axis is (Assuming initial speed to be zero.)

$A$ body is falling freely from the top of a tower of height $125 \ m$. The distance covered by the body during the last second of its motion is $x \%$ of the height of the tower. Then $x$ is (Acceleration due to gravity $= 10 \ m/s^2$)