Weighing Machine — ElevatorHardQuestion 30232
Question
A person of mass 70 kg stands on a weighing scale in a lift. The scale reads 56 kg. The lift is moving with:
- AAcceleration 2 m/s² upward
- BAcceleration 2 m/s² downwardCorrect
- CConstant velocity upward
- DNo motion
Correct answer
Acceleration 2 m/s² downward
Explanation
Apparent mass = true mass × (g−a)/g. 56 = 70×(10−a)/10 → 8 = 10−a → a = 2 m/s² downward.