Question

A body projected vertically up with a velocity 'u' attains a maximum height H. If it is thrown up with velocity 2u, it attains a maximum height of ___________.

• A. 2H
• B. H/2
• C. 4H
• D. H/4

Answer 1

The correct option is C 4H

Velocity at the maximum height $v=0$

Acceleration $a=-g$

Using $v^2-u^2=2aH$

$\therefore$ $0-u^2=2(-g)H$

$⟹H=\frac{u^2}{2g}$

We get $\frac{H_2}{H_1}=\frac{u_2^2}{u_1^2}$

or $\frac{H_2}{H}=\frac{(2u{)}^2}{u^2}=4$

$⟹H_2=4H$