So for school I'm designing a ramp. The problem is that I need to calculate various things in it, none of which I've ever been taught, since I'm pretty sure it's all uni level. I've asked multiple teachers, including my physics teacher and my technology teacher, and they haven't been any help. Basically, my ramp is a 50.8 mm square aluminium tube with 3.25mm walls, which is 2m long. I want it to be able to hold at least 200kg, which I guess can be modeled as a point force in the middle (i.e. 1m). However, I don't have a clue how to calculate the bending moment, so that I can calculate the strength of the beam (via it's section modulus, which I have figured out). The ramp is supported at both ends and can be modeled as being horizontal. I've looked on the internet, but nothing makes any real sense. I don't want the solution as much as I want an explanation on how to calculate the bending moment.