An elevator in which a man is standing is moving upwards with a speed of 10m/sec . If the man drops a coin from a height of 2.45 metre, after what time it reaches the floor of the elevator.

Explanation

Hereu=0 beacause lift is moving. Relative velociy of coin w.r.t lift is zero,
a `a = + g = 9.8 m/s^2 t = ? s = 2.45 m`
`As S = ut+1/2xx9.8t^2=4.9t^2`
`t^2 = 2.45/4.9 = 1/2 or t = 1/(sqrt2sec)`