Physic Labs

Problem 1

Two masses m1m_1 and m2m_2 (m2>m1m_2>m_1) are joined by a light inextensible string over an ideal pulley; m1m_1 is on an incline of angle α\alpha with kinetic friction coefficient μ\mu, and m2m_2 hangs vertically. With constant gg, find the acceleration and string tension as m2m_2 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.
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fk=μm1gcos⁡αf_k=\mu m_1g\cos\alpha
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The kinetic-friction law gives magnitude μN\mu N; its direction is down the plane because the block moves up it. This is consistent with the stated model and the chosen sign convention.