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Both sides of wire start out with 5 washers with the total mass of 5m.  When N washers are transferred from the left side to the right side, the right side descends 70.56 cm in 0.60 s. Find N.

It is not clear whether the total weight of all washers is 5m or 10m.   I assume the latter so each washer weighs m.

When N washers are transfered from one side to the other, the difference in weight between the two sides becomes 2N * mg.   This force creates the acceleration that all ten washers (mass = 10m) will experience.

To calculate the acceleration based on time and distance use d = 1/2(a)(t)^2.   a = 2d/t^2.

To calculate the acceleration based on the weight difference.     a = 2*N*mg/10m.

Set these two expressions for a to be equal.   2(.706)/(0.6^2) = 2*N*9.8/10

N = (.706/.36)* 10/9.8 = 2 Washers transfered.

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