Homework Help Forum: Physics

Posted by Matthew on Thursday, October 8, 2009 at 11:43am.

This is another problem that I need clarification on since no one seems to be of any help at my school, A pulley system is used to lift a 52- crate.Note that one chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to the crate. Assume the masses of the chains, pulleys, and ropes are negligible. Determine the force required to lift the crate with constant speed. Determine the tension in the upper chain, and lower chain. C ( ) | O | | | \ | | \ | | (Force via hand) O ) | [52kg] Sorry for such a crude drawing but if you imagine the lines as the rope, the parentheses as curves in the line, and O's as the pulleys. C = Cieling

• Physics - Matthew, Thursday, October 8, 2009 at 12:16pm

  My thoughts were that tension must be halved in one sense or another, but I cant seem to get the math to work out involved, perhaps Im missing the equations entirely.

  
  

• Physics - bobpursley, Thursday, October 8, 2009 at 12:23pm

  Actually, the Mechanical advantage is two(two ropes are pulling on the 52kg mass, so you are right. Tension is 52g/2 The tension in the upper, and lower rope is 52g I am not certain what equations you are working with. At the lower pulley, Let T up be + T+T-mg=0

  
  

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