Question

A Spring Balance Is Attached To The Ceiling Of A Lift. A Man Hangs His Bag On The Spring And The Spring Balance Reads 49N, When The Lift Is Stationary. If The Lift Moves Downward With An Acceleration Of 5M/s^-2, The Reading Of The Spring Balance Will Be. a)24N b)74N c)15N d)49N

Answer 1

Free Body Diagram of the bag when the lift accelerates downwards is given below.

The spring balance reads the actual weight of the bag, i.e., 49 N, when the lift is stationary.

Hence the mass of the bag is,

Then the reading of spring balance will be R when the lift accelerates downwards. R is the new weight of the bag.

The acceleration is,

Hence from the free body diagram of the bag, the net force acting on the bag is,