A block is suspended from a spring balance inside a lift
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
A 20kg block is suspended from a spring balance inside a lift. Assume the spring balance is calibrated to read the force exerted on the block.
(a) Show that when the lift is at rest the reading of the spring balance equals the true weight of the block.
(b) Derive an expression for the reading R of the spring balance when the lift accelerates downward with acceleration a.
(c) Using your expression, find the reading when the lift is in free fall.
(d) Determine the magnitude and direction of acceleration of the lift if the spring balance reading becomes twice the true weight of the block.