An object is thrown vertically upwards. At its maximum height,which of the following quantities becomes zero?

$A$ food packet is dropped from a helicopter rising up with a velocity of $4 \, ms^{-1}$. The velocity of the packet after $3 \, s$ will be ....... $ms^{-1}$. (in $.4$)

If the water falls from a dam into a turbine wheel $19.6 \ m$ below,then the velocity of water at the turbines is .................. $m/s$ (take $g = 9.8 \ m/s^2$).

$A, B, C$ are points in a vertical line such that $AB = BC$. If a body falls freely from rest at $A$, and $t_1$ and $t_2$ are the times taken to travel distances $AB$ and $BC$ respectively, then the ratio $(t_2 / t_1)$ is:

$A$ student performs an experiment to determine the acceleration due to gravity $g$. The student throws a steel ball up with initial velocity $u$ and measures the height $h$ travelled by it at different times $t$. The graph the student should plot on a graph paper to readily obtain the value of $g$ is

$A$ parachutist after bailing out falls $50\, m$ without friction. When the parachute opens,it decelerates at $2\, m/s^2$. He reaches the ground with a speed of $3\, m/s$. At what height did he bail out (in $, m$)?