Question

A body of mass 2 kg is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity ‘g’, the reading on the spring balance will be

• A. 2 kg
• B. (4 ×g) kg
• C. (2 ×g) kg
• D. Zero

Answer 1

Answer: (D)

Zero

Answer 2

$R = m(g - a)$ $= (g - g) = 0$

[because the lift is moving downward with a = g]