Question

A man of weight w is standing on a lift which is moving downward with an acceleration a.the apparent weight of man is?

Answer 1

Answer; mg - ma where mg = w= weight of the person

                                                               

Explanation: As the man is on the lift so the man is pulled by gravity by a force (mg). And the floor of the lift will apply an upward force called reactioin(R) or normal force on the man. Under equilibrium or if the lift is at rest  R=mg.But in this case as the lift is accelarating downward so mg> R.

Therefore the net force experienced by the man in the lift will be

     mg - R= ma

or   R = mg-ma

this R is the apparent weight.