Question

A ball is dropped from a height. If it takes 0.200 s to cross thelast 6.00 m before hitting the ground, find the height from which it was dropped. `Take g=10 m/s^2`.

Answer 1

Correct Answer - B
For last 6 m distance tavelled, `S= 6m, u=?, t=0.2 sec, a=g= 9.8 m/s^2, S= ut+ 1/2 at^2, 6=u(0.2)+4.9xx0.04, rarr u=5.8/0.2, 29 m/s`, For distance `x, u=0, v= 29 m/s, as=g= 9.8 m/s^2, :. S_2 = (v^2-u^2)/(2a), = (29^2-0^2)/(2xx9.8)=(29xx29)/19.6, Total distance = 42.5+6=48.5m = 48`