Homework Help: Tension of Suspended Cable

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1. Mar 23, 2016

Ellen W.

1. The problem statement, all variables and given/known data
A 50.0 kg 6.00m awning is held up by a wire in the middle. A 15kg sign hangs at the end. Calculate the tension in the massless wire and the magnitude of the net force from the wall acting on the awning.
The cable forms a 40 degree angle with the awning at the bottom right corner.
2. Relevant equations
Sum or Torque

3. The attempt at a solution
Sum of Torque=0=(mg)(L)+(Mg)(L/2)-(T)(L/2)Sin40)
L's cancel
(mg)+(Mg/2)=Tsin40/2
(mg)+(Mg)/sin40=T
((15*9.81)+(50*9.81)/sin40)=T
T=992N
???
I'm not sure what the question means by net force from the wall. Is it just the normal force of the wall or do I have to use the tension to find it?

2. Mar 23, 2016

TSny

Careful with treating the 2's.
What can you say about the net force on the system?

3. Mar 23, 2016

Ellen W.

The net force would have to be zero. Does this mean that they are equal?

4. Mar 24, 2016

TSny

It means ∑Fx = 0 and ∑Fy = 0. The wall exerts a force on the awning that could have both and x and y components.