Question

A stone thrown vertically upwards with a speed of 5 m/sec attains a height $H_1$. Another stone thrown upwards from the same point with a speed of 10 m/sec attains a height $H_2$. The correct relation between $H_1$ and $H_2$ is

• A. $H_2=4H_1$
• B. $H_2=3H_1$
• C. $H_1=2H_2$
• D. $H_1=H_2$

Answer 1

Answer: (A)

From third equation of motion $v^2=u^2+2ah$
In first case initial velocity $u_1=5m/\sec$
final velocity $v_1=0,a=-g$
and max. height obtained is $H_1$, then,
$H_1=\frac{25}{2g}$
In second case $u_2=10m/\sec ,v_2=0,a=-g$
and max. height is $H_2$ then, $H_2=\frac{100}{2g}$
It implies that $H_2=4H_1$