A lift is moving down with acceleration a

A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively

  1. g, g
  2. a, g
  3. g-a, g-a
  4. g-a, g

Answer

Apparent weight of the ball is W'= W-R

R = ma (Acts upward)

W' = mg - ma = m(g-a)

Hence, the apparent acceleration in the lift is g-a and for the person standing outside the acceleration of the falling ball is g.

The correct option is D.