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

$g–a,g$

Step 1: Given data

Acceleration of the lift w.r.t ground, $a_{lg}=a$

Step 2: Find acceleration of ball w.r.t ground and the person who is standing in the lift

Acceleration of ball w.r.t. ground, $a_{bg}=g$

Acceleration of ball w.r.t. to the person who is standing in the lift, $a_{bl}=a_{bg}-a_{lg}$

$=g-a$

Hence, option (C) is correct.