Laws of MotionHard
Question
A body of mass 32 kg is suspended by a spring balance from the roof of a vertically operating lift and going downward from rest. At the instants the lift has covered 20 m and 50 m, the spring balance showed 30 kg & 36 kg respectively. The velocity of the lift is:
Options
A.decreasing at 20 m & increasing at 50 m
B.increasing at 20 m & decreasing at 50 m
C.continuously decreasing at a constant rate throughout the journey
D.continuously increasing at constant rate throughout the journey
Solution
N = m (g − a) , N < mg if a (↓)
and N > mg if a (↑)
Reading of spring balance is less than m
if a (↓) and reading of spring balance is

greater than m if a (↑)
and N > mg if a (↑)
Reading of spring balance is less than m
if a (↓) and reading of spring balance is

greater than m if a (↑)
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