Solve Intermediate Materials Statics Problem: Deflection, Internal Forces

[billybob70]

This is a problem for an intermediate materials class. There is a RIGID beam (does not bend) that is pinned at the top and has a 220 lb force on the bottom. There are two cables holding it in place (See diagram below).

we are supposed to find the deflection of the beam at the bottom, and the internal forces in the wires.

This problem looks to me like it is statically indeterminate. I cannot figure out which point i should sum the moments at--there are always too many unknowns.

 

[billybob70]

i think i figured it out, so you can remove this thread if you want

 

[piercas]

I would approach this problem by first identifying the key variables and equations involved. In this case, we have a rigid beam that is pinned at the top and has a 220 lb force acting on the bottom. Additionally, there are two cables holding the beam in place. To solve for the deflection of the beam and the internal forces in the cables, we would need to use equations related to statics and mechanics of materials.

One possible approach to solving this problem would be to use the principle of superposition, which states that the total deflection of a structure is equal to the sum of the deflections caused by each individual load acting separately. In this case, we could consider the beam with the 220 lb force acting on it alone, and then add the deflection caused by the two cables acting separately. This would allow us to solve for the deflection of the beam at the bottom.

To determine the internal forces in the cables, we could use equations related to equilibrium and the geometry of the system. By summing the forces and moments acting on the beam and cables, we could solve for the unknown internal forces in the cables.

Overall, this problem requires a combination of knowledge in statics and mechanics of materials to solve. It is important to carefully consider all the given information and use appropriate equations and principles to arrive at a solution.