simple pulley problem, two weights connected by a taut cord are hanging freely on either side of a pulley. The mass on the right is M, the mass on the left is m. The cord connecting the two masses is negligible and does not stretch (no acceleration) and the pulley does not retard the motion either.
I want to find an expression for the acceleration of the system, in terms of the masses M,m
The answer should be a = ( M- m ) / (M+m) * g
which I do not get. Here is my work and diagram.

Question

simple pulley problem, two weights connected by a taut cord are hanging freely on either side of a pulley. The mass on the right is M, the mass on the left is m. The cord connecting the two masses is negligible and does not stretch (no acceleration) and the pulley does not retard the motion either.
I want to find an expression for the acceleration of the system, in terms of the masses M,m
The answer should be a = ( M- m ) /  (M+m) * g
which I do not get. Here is my work and diagram.

perl · Answer

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