Pulley system?

If I have two masses A = 2kg and B=4kg,

in a system that I am going to describe, what is the resultant tension in the string?

Basically, you have a smooth horizontal table, A rests on the table and is attached to a string which is attached to B.

B is hanging freely from one side of the table such that when time is resumed, B will fall and drag A with it.

How is the resultant tension 40/3 N please?

Thank you in advance!


Assume g is 10

1 Answer

  • 6 years ago

    The total mass of the system is 6 and only the 4kg weight is providing acceleration to the system.

    F=ma 4*10 = 6*a or the acceleration of the system after you let go is 20/3

    Now the tension in the string is totally due to the 2kg mass. If the mass were zero there would be no tension in the string---just a free falling 4kg mass.

    So F (2kg mass) = T = ma = 2*20/3 = 40/3

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