# Homework Help: Pulley question to determine the weight at a certain angle

1. Apr 11, 2012

### bobmarly12345

1. The problem statement, all variables and given/known data
An assembly shown in the picture, GH , HK, HNL are three cables. the mass of box L is 52Kg,
a) determine the mass of box K in order to make angle theta as 25 degrees

2. Relevant equations
Fx=0
Fy=0

3. The attempt at a solution
Fhn x cos(25) = Fhg x cos(0)
fhn x sin(25) = 52kg
fhn(sin25 x cos25) =39kg

doesnt look right to me. steps on how to do it would be great & guidance through it rather than telling me its a static equillibrium question or just over complicating it. thank you for giving it a look

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2. Apr 11, 2012

### PhanthomJay

that's Fxnet =0 and Fynet = 0. Yep!
yes, good
hmmm, if you look at the box L of mass = 52 kg, then the tension force in NL is ??? And then HN = NL.
What's this?

Once you get HN by looking at the forces acting on L and using Newton 1 to solve forn NL. Now you calculate Fhg from your first equation.

At joint H, the vert comp of HN must equal the tension in HK, per newton 1 in the y direction, and then look at the forces acting on K to solve for its mass .
doesnt look right to me. steps on how to do it would be great & guidance through it rather than telling me its a static equillibrium question or just over complicating it. thank you for giving it a look[/QUOTE]