# Shear and Moment diagrams

There are two forces in every simple beam diagram. Vertical loads and moment loads. Think of moment force as the turning force. The moment force at both A and B is 0. This because the beam is free to rotate if there was moment force the beam would spin. Let solve the 2 forces.

1. Solve sum (Σ) all the forces in the vertical or y direction(fy). Note the forces in the up direction are positive and the ones down are negative. Force at A is call FyA and Force at B is call FyB Hint: there are two variables so the equation can’t be solved

2. Solve the Sum (Σ) of all the moment forces at point A (Ma). This is 0 as stated before ΣMa=0. Moment forces units are measured in load*distance from the point we are measuring. There for we can add all of the forces x distance and find the missing variable.

3. Calculate FyA x distance. This will equal 0 and can be ingored

4. Calculate the equivalent load of the distributed load. this is weight x length.We then have to find the location of this equivalent load. This happens at the mid point of the distributed load. The force is equivalent weight x distance from A Keep in mind Negative is down.

5. Calculate the point load. Weight x distance from point A

6. Calculate the fyB. Weight x distance from point A. Keep in mind positive is up.

7. Solve for fyB this is the only variable in the equation. because fya =0 and Ma =0.

8. solve for fya. fya can be solved using the equation in step 1.

This video may help. Post your steps and or questions below and I check them.