A student of mass stands barefoot on a spring balance placed on the floor of an elevator
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
A student of mass 60kg stands barefoot on a spring balance placed on the floor of an elevator. Treat the student as a single particle located at his centre of gravity.
(i) Draw a free-body diagram for the student when the elevator is (a) at rest, (b) accelerating upward, and (c) accelerating downward.
(ii) Explain qualitatively how the reading of the spring balance differs in the three situations mentioned in part (i).
(iii) When the elevator cable suddenly snaps and the cabin is in free fall, what will the spring balance read? Give reasons for your answer.
(iv) State why the quantity measured by the spring balance in a moving elevator is called the “apparent weight” of the student.