Okay, this is definitely a simple question to start with.
Question: If x= L/3 what is the vertical reaction at support A?
Solution: To solve this we need to take moment about a point that we know the moment for. Point B is a pin support for must have zero moment.
- So taking moments about B we have acting clockwise the moment generated by the vertical reaction A (Va * L).
- This must be equal to the anticlockwise moments generated by the applied loads, which are equal to
- P*(2L/3) for the moment from the point load
- (wL/2)*(L/4) for the uniform loading - the first term in brackets is the total load the second term is the lever arm to the centre of the load.
3. equating clockwise and anticlockwise and dividing by L we get Va=(2P/3) +(wL/8)