Question

A person is sitting in a lift accelerating upwards. Measured weight of person will be

• A. less than actual weight
• B. equal to actual weight
• C. more than actual weight
• D. None of the above

Answer 1

Answer: (C)

When a person of mass m is placed on a weighing machine which is placed in a lift, For minimum wavelength of Balmer series, then actual weight of the person is mg. This acts on a weighing machine which offers a reaction R given by the reading of weighing machine. This reaction exerted by the surface of contact on the person is the apparent weight of the person.
When lift is accelerating upwards at the rate of $a$ , then reaction
$R-mg=ma$ $\therefore$ $R=m(g+a)$