Single correct option
A person stands on a weighing machine in a lift that is accelerating upward. The reading of the machine will be
- A. less than the actual weight of the person
- B. greater than the actual weight of the person
- C. equal to the actual weight of the person
- D. zero
Show answer and solution
Answer: (B) greater than the actual weight of the person
The machine reads the normal reaction N. For upward acceleration a, N - mg = ma, so N = m(g + a), which exceeds mg. The reading would be less than the weight for downward acceleration and zero only in free fall. At constant velocity the reading equals the actual weight, which is the common mistaken answer.
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