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FInd the maximum speed Block C, with mass m c rests on block A, with mass m a, w

ID: 1287011 • Letter: F

Question

FInd the maximum speed

Block C, with mass mc rests on block A, with mass ma, which in turn is on a horizontal tabletop. The coeefficient of kinetic friction between block A and the tabletop is uk, and the coefficient of static friction between block A and block C is us. A light string attached to block a passes over a frictionless, massless pulley and block B is suspended from the other end of the string. What is the largest mass mb that block B can have so that blocks A and C still slide together when the system is release at rest? Answer in a simplfied form

Explanation / Answer

max frictional force given by A on C=us*mcg

max accn= us*mcg/mc=usg

it the maximum acc of system when  that blocks A and C still slide together when the system is release at rest.

T-uk(ma+mc)g=us(ma+mc)g.....1

mbg-T=usgmb

T=mbg-usgmb....2

putting 2 on 1

mbg-usgmb-uk(ma+mc)g=us(ma+mc)g

mb(1-us)=(ma+mc)(uk+us)

mb=(ma+mc)(uk+us)/(1-us)