Question

How does the weight of a man standing on a lift changes when the lift accelerates upwards and downwards with an acceleration "a"? Also discuss the variation of weight when the lift moves with uniform velocity and fall freely?

Answer 1

Acceleration of the lift = a

Let the mass of the man be "m".

a) When the lift is accelerating upward, the apparent weight of the man increases = m (g + a)

b) When the lift is accelerating downward, the apparent weight of the man decreases = m (g - a)

c) When the lift is moving with a constant velocity, the apparent weight will be equal to the true weight = mg

d) When the lift is free falling, the apparent weight of the man becomes zero as the normal force is zero = m (g - g) = 0