We’ve been studying statics in our physics class. We have examined how to calculate the forces in ropes and cables that support hanging objects. Up to this point, we’ve only considered the cases where the cables are symmetric (make the same angle with the horizontal).
Consider (the somewhat unorthodox) case where a sign is hung by two cables that *are not* symmetric—here, the cables each make different angles with the horizontal. Let’s do some work to calculate the force in each cable:
- Suppose the sign’s mass is 5 kg. What is the weight of the sign?
- Call the tension in the left cable FL and the tension in the right cable FR. Write an expression for FLx, FLy, FRx, and FRy.
- Write an equation relating the forces in the vertical direction. (HINT: Think balanced.)
- Write an equation relating the forces in the horizontal direction. (HINT: Think balanced.)
- Notice you should now have two equations with two unknowns FL and FR. Solve the resulting system to find the tension in each cable.
