A crate is held motionless between two vertical warehouse walls by workers who press…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A 20kg crate is held motionless between two vertical warehouse walls by workers who press horizontally on the crate. Each worker exerts a horizontal force F on opposite sides of the crate so that the crate does not slide up or down.
(a) Given that the coefficient of static friction between all contact surfaces (crate–wall) is μs=0.60, determine the minimum value of F each worker must apply to keep the crate at rest.
(b) After a brief period, one worker steps away while the other continues to push horizontally on one side only. Calculate the new minimum horizontal force that the single worker must exert to prevent the crate from sliding. State any assumptions clearly.
(c) If instead the coefficient of kinetic friction were relevant, describe qualitatively how the required horizontal force would change once the crate began to slide.