Three block, connecting ropes, and a light frictionless pully comprise a system, as shown. An external force P is applied downward on block A. The system accelerates at the rate of 2.5m/s2. The tension in the rope connecting block B and block C equals 60 N. I dont have a picture but ill discribe it.(adsbygoogle = window.adsbygoogle || []).push({});

Ok there are two masses on one side of the pully B and C. B is on top and C is on bottom, the Force exerted on B by C is 60N. Mass of B is 18kg. Then there is a mass on the other side which has a mass of 12Kg.

Ok i tired this problem but i keep getting the wrong answer.

The total force on B is

T - (60 N + w_{B}) = m_{a}a

and then the total force on B is

T - w_{A}= -m_{a}a

Since A is accelerating downwards it has a negative acceleration and B has a positive accleration.

The answer should be 190N but i cant seem to get the answer. What am i doing wrong.

Thanks

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# Homework Help: A question about masses on a pully

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