question_answer

A man stands in a lift going downward with uniform velocity. He experiences a loss of weight at the start but not when lift is in uniform motion. Explain why?

Answer:

                The apparent weight is given by \[R=W-ma=mg-ma\] or \[R=m(g-a)\] Since lift is in acceleration in the start, \[a\ne 0,\] so \[R<mg.\]When lift comes in uniform motion, acceleration ceases \[(a=0)\] and man experiences his own weight.