Problem 1
Two masses and () are joined by a light inextensible string over an ideal pulley; is on an incline of angle with kinetic friction coefficient , and hangs vertically. With constant , find the acceleration and string tension as descends. Assume the string, pulley, electrical source, or optical apparatus is ideal as stated, and neglect any effect not specified. State a clear sign convention, identify the physical Keep one model and sign convention throughout. Reuse each intermediate result with the same convention, then check that the answer has the required physical dimensions. (a) Set up the physical relation. (b) Find an intermediate quantity. (c) Obtain the answer and check its conditions and units.
problems.proof.stepOf
problems.proof.analysis
Substitution into the hanging-mass equation determines tension; using either body must give the same value. This is consistent with the stated model and the chosen sign convention.
problems.proof.pitfall. Do not reverse friction: it always opposes relative sliding.