Question

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

• A. $g,g$
• B. $g-a,g-a$
• C. $g-a,g$
• D. $a,g$

Answer 1

The correct option is C $g-a,g$

Man in lift is in non-inertial frame. By applying psuedoforce on the ball,we get net acceleration $=g-a$ w.r.t. lift,

As earth is assumed to be inertial frame, no pseudo force acts. So FBD is

Hence $a_{\text{net}}=g$