Question

The ball is thrown vertically up (taken $+z-$ axis) from the ground. The correct momentum-height $(p-h)$ diagram is:

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

Using equation of motion,
$v^2=u^2-2gh$
or $v=\sqrt{u^2-2gh}$
Momentum, $p=mv$
$\therefore p=m\sqrt{u^2-2gh}$

Therefore, graph between $p$ and $h$ cannot be a straight line.
i.e (b) and (c) are not possible.
During upward journey as $h$ increases, $p$ decreases and in downward journey, as $h$ decreases, $p$ increases in negative direction.
Therefore (d) is the correct option.