If the tension in the string in figure (6-E3) is 16 N and the acceleration of each block is 0.5 m/s2, find the friction coefficients at the two contacts with the blocks.




The free body diagram of the given problem is shown above.


From figure (a)


μ1R + ma = T


μ1R + 2(0.5) = 16 {R = mg cosθ}


μ1(2g) =15


μ1 = 0.75


From figure (b)


μ2R + ma = F mg sin θ


μ2mg cos θ + 4 (0.5) = 16 − 4g sin 30°


μ2 = 0.06


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