Shear Force Example (Beginner)

As discussed in the previous post, Shear Force is one of the simplest yet strangely difficult topics to learn and get your head around. But with a few examples you should be able to go into an exam and get 100% on this type of question.
The best thing about this type of question is that the end answer has to be zero making the beam in equilibrium. Therefore you always know if you have succeeded and got the physics and mathematics right.


The first example is a relatively simple on, shown below is beam and the calculations to get the final answer. The beam is simple support (I.e two supports in the Y direction) and contains a distributed load which constant as well as an ultimate force.

The first step is to write down the Formula's for Force in the Y direction. There is no force in the X direction which makes these questions even easier. You should then be left with two unknowns, and therefore we need to use moments to calculate one of the unknowns and then put the data back into the Forces in Y to get the final unknown. These unknowns will always be the Reactions of the Supports unless stated. The diagrams have to be drawn to show the shear force.

The Final step is calculate the bending moment which is a little more complicated due to the moment acting at a distance from the point you choose. This is again shown in the example with the Bending Moments diagram drawn at the end. From this you can then calculate the Maximum Bending Moment but this will be done in a later example.