A body of 2 kg is suspended on a spring balance hung vertically in a lift . If the lift is falling downward under acceleration due to gravity g then what will be the reading of the balance ? If going upward with the same acceleration then ?

Explanation

Reading of the balance = apparent weight ` = m (g-a) = m (g - g ) = zero `
If lift is going upwards with same acc ,
` W = m (g - a ) = 2 m g = 4 kg` .