Question

A body falls for $5s$ from rest. If the acceleration due to the gravity of earth ceases to act, The distance travels in the next $3s$ is.

• A. $73.5m$
• B. $294m$
• C. $147m$
• D. $49m$

Answer 1

The correct option is D $49m$

Initially the body starts its motion from rest therefore $u=0$. Let journey be $A$ when a acceleration of earth is acting on the body time $=5$ seconds let's find $v$

$v=u+at$

$=0+9.8\times 5=49m/s$

When acceleration stops acting the velocity of the body is $49m/s$. Now the distance traveled by the body in next $3s$

$S=ut+\frac{1}{2}{gt}^2$

$=49\times 3+\frac{1}{2}\times 0\times t^2$

$=49\times 3$

$=147m$.