Ah, that one used to trip me up too. The normal force has to do more than just balance mg when the lift accelerates—it also provides the extra push to accelerate you upwards, so it becomes *more* than mg. I picture it like carrying a sack of rice into my third-floor flat; when you heave it up faster, you feel the extra strain in your arm. I missed this very question in the NPSC exam, because I was too busy worrying about my mother's blood pressure that morning to focus on the "obvious" revision.
#exams#study
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