Question

Suppose there is still air. Now a stone, a piece of paper and a coconut are thrown vertically with the same speed. Which one will go highest

• A. Stone
• B. Paper
• C. Coconut
• D. All will rise the same height

Answer 1

Answer: (D)

All will rise the same height

Acceleration due to gravity $\left(g\right)$ acts on the objects downwards so that the objects fall in downward direction. But this acceleration due to gravity $(g=9.8m/s^2)$ is same for all the objects irrespective of their masses.

Let the speed with which the objects are thrown vertically upwards be $u$ and maximum height reached be $H$.

At maximum height, the final speed of the objects is zero i.e. $v=0$.

Using $v^2-u^2=2(-g)H$ (Taking upward direction to be positive)

$\therefore$ $0-u^2=-2gH$

$⟹$ $H=\frac{u^2}{2g}$ which is same for all objects because $u$ and $g$ are same for all objects.

Hence a stone, a piece of paper and a coconut will rise to the same height when they are thrown with same upward velocity.