Imagine yourself standing in an elevator while is moving with an upward acceleration `a = 2 m//s^2`. A coin is dropped from rest from the roof of the elevator, relative to you. The roof to floor height of the elevator is `1.5 m`. `("Take" g = 10 m//s^2)`. Find the velocity of the coin relative to you when it strikes the base of the elevator.

Options

A. `3 m//s`
B. `6 m//s`
C. `2 m//s`
D. `1.5 m//s`

Answer

B

Explanation

Using `v_r^2 = u_r^2 + 2 a_r s, u_r = 0`
`a_r = g-(-a) = (g + a)`
`v_r^2 = 0 + 2 (g + a) . h`
`v = sqrt(2(g + a)h) = sqrt(2 xx 12 xx 1.5) = 6 m//s`.