Question

lift is moving downward with constant velocity of 10 metre per second a coin is dropped at a height of 5 metre from the floor of lift find the time taken by coin to reach the floor

Answer 1

Answer:

(A) 1 s

Explanation:

1) Observing the situation with respect to lift,

Convention : Downward direction is positive $S_{rel}=5 m$

Since, coin is at rest with respect to lift .

$u_{rel}=0 m/s$

Acceleration of lift is 0, but that of coin is g.

$a_{rel}=10m/s^2$

2) Using Newton's Equation of motion,

$S_{rel}=u_{rel}t+\frac{1}{2}a_{rel}t^2\\ \\=>5=0*t+0.5*g*t^2\\ \\=>5=0.5*10*t^2\\ \\=>5t^2=5\\ \\=>t^2=1\\ \\=>t=1s$

Hence, time taken by coin to reach the floor is 1s.

Answer 2

Answer:

Please refer to the attachment.

Ans- 1 s