alleryStart learning →A person stands on a bathroom scale inside a lift. The lift begins to accelerate downwards and the person feels lighter. Which force has become smaller?
AThe normal force
BThe force of gravity
CThe force of friction
DThe force of tension
Answer & Solution
Correct answer: A. The normal force
1. The gravitational force on a person depends on their mass and on gravitational acceleration, neither of which the lift changes.
2. A scale actually measures the normal force pushing up on the person standing on it.
3. Accelerating downwards needs a net downward force on the person.
4. That net downward force appears because the upward normal force drops below the downward gravitational force.
5. The scale reading therefore falls and the person feels lighter, a phenomenon called apparent weight.
6. Naming gravity as the shrinking force is the trap here, because the actual weight has not changed at all.
_Source: Siyavula Physical Sciences Grade 11 (Everything Science, CC BY 4.0), Chapter 2: Newton's laws_
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