PHYSICS · Single correct · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
A small camera floats freely inside an elevator. An observer inside the elevator notices that the camera remains fixed at eye level without drifting toward any wall. Based on this observation, which description of the elevator’s motion relative to Earth is most consistent with Newton’s first law?
(a) The elevator is either at rest or moving at constant velocity; a normal force balances gravity on the camera.
(b) The elevator is accelerating upward; the upward inertial force on the camera cancels its weight, so it floats.
(c) The elevator is accelerating downward; the camera has no apparent weight under these conditions.
(d) The elevator is moving in a vertical circle, and the required centripetal force keeps the camera suspended.