A lift that forms part of a prototype space-elevator moves vertically upward from the…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
A lift that forms part of a prototype space-elevator moves vertically upward from the Earth’s surface to a small height h (h≪R) at a constant speed. A student of mass m stands on a properly calibrated bathroom scale kept on the lift floor.
(i) Explain whether the reading of the scale equals the true weight of the student while the lift is moving at constant speed.
(ii) Taking into account the fact that the value of g decreases with altitude, describe qualitatively how the scale reading changes as the lift ascends from the ground to the height h.
(iii) State any two distinct conditions under which the scale reading would have exactly the same magnitude as mg measured on the ground, and justify your answer in each case.