Question

Two bodies, one held 30 cm directly above the other, are released simultaneously and allowed to fall freely under gravity. After 2 s their relative separation will be :

• A. 10 cm
• B. 20 cm
• C. 30 cm
• D. Zero

Answer 1

The correct option is C 30 cm

Initial speed of the body $u=0$

Distance covered by a body in time $t$, $S=ut+\frac{1}{2}g{t}^2$

Or $S=0+\frac{1}{2}g{t}^2=5t^2$ $(\because g=10m/s^2)$

For body 1 :

$S_1=5\times 2^2=20m$

For body 2 :

$S-2=5\times 2^2=20m$

Thus both the bodies cover equal distance in 2 seconds. So the final separation between the bodies is equal to the initial separation between them i.e. $30cm$.