A man of mass m is standing on a lift which moves down with an upward acceleration a. Find the pseudo force acting on the man as observed by himself. Find the pseudo force acting on the man if the lift falls freely.

Explanation

The pseudo force is observed from acceleration obeserver and acts in the direction opposite to the direction of the observer and magnitude is equal to mass of the object multiple by the acceleration of the observer.
Hence `F_(pseudo)=ma`(downward) because the direction of the acceleration on the lift is in upward direction. If lift falls freely, the acceleration of the lift along with observer will be in downward direction and equal to acceleration due to gravityl. So the direction of pseudo force will be in upward direction and magnitude is equal to
`F_(pseudo)=mg`(upward)