Question

Two bodies of different masses are dropped from heights of 2 m and 8 m respectively then the ratio of the time taken by them is:

• A. 1:4
• B. 1:1
• C. 1:2
• D. 1:3

Answer 1

The correct option is C 1:2

The balls are dropped from heights of 2m and 8m. Their initial velocity is zero.
Using the equations of motion
$s=ut+\frac{1}{2}a{t}^2$
$s_1=\frac{1}{2}g{t}_1^2$
$s_2=\frac{1}{2}g{t}_2^2$
$s_1:s_2=\frac{t_1^2}{t_2^2}$
$t_1:t_2=1:2$