A person of mass is standing on a weighing machine inside a lift that can move only…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
A person of mass 65kg is standing on a weighing machine inside a lift that can move only in the vertical direction.
(a) Derive a general expression for the normal reaction N exerted by the machine on the person when the lift moves with a uniform acceleration a (take the upward direction as positive). Clearly state the cases that lead to an increase or decrease in the scale reading.
(b) While the lift is moving, the machine shows a reading of 480N. Find the magnitude and direction of the lift’s acceleration at that instant.
(c) If the lift were to move with the same magnitude of acceleration in the opposite direction, what would be the new reading on the weighing machine?