Rankers Physics
Topic: Kinematics
Subtopic: Motion Under Gravity

A body is dropped from a tower. It covers 64% distance of its total height in last second. Find out the height of tower [g = 10 ms–²]
31.25 m
25.31 m
40 m
125 m

Solution:

\[ 0.36 H= \frac{1}{2}g(t-1)^{2} \]

\[ H= \frac{1}{2}g(t)^{2} \]

Dividing we get

\[ 0.36 = \frac{(t-1)^{2}}{t^{2}} \]

\[ 0.6 = \frac{(t-1)}{t} \]

0.4t =1

t= 2.5 sec

S= (1/2) ×10 ×(2.5)²= 31.25 m

Leave a Reply

Your email address will not be published. Required fields are marked *