ƩƩ1. The problem statement, all variables and given/known data I am having issues finding Ra and Rb using the Sum of the momemnts, it's ƩMCW = MACW. I need to find the position of the maximum and minimum bending moments. The Supported beams in question is 3.5m long. Starting from the left and moving towards the right: 1m in and then a 2KN load, then 1.5m further in and then another load of 3KN hits down and then an extra 1m when it meets the end. Like this: 1m, 2KN, 1.5m, 3KN, 1m. Ra Rb Looking at my notes for some example i did (didn't finish the notes, must of forgot and now paying the price), example i did: 3m, 4KN, 4m, 3KN. Ra Rb And here are the notes: ƩMCW = MACW (4x3) + (3X7) = Rb x 12 12 + 21 =Rb x 12 33/12 = Rb =2.75KN ƩFup = ƩFdown Ra + Rb = 4+3 Ra + 2.75 = 7 Ra = 7 - 2.75 Ra = 4.25KN In the Engineering book i brought: Engineering Science by Mike Tooley and Lloyd Dingle, there is a beam example: 2m, 20KN, 3m, 5KN, 2m, 30KN, 2m, 15KN. Ra Rb He did this: 2x20 + 5x5 + 7x30 + 9x15 = 8xRb Using this example and my own, i attempted to answer the question to find Ra and Rb. The very first and poorly drawn supported beam at the top. 2. Relevant equations Direct Stress σ = F/A = Force/Area n/m squared Sheer stress ζ = F/A = Force/Area n/m squared Strain ε = Δ x L/L = Change in length/Original length. Modulus of elasticity E = σ/ε = stress/strain N/M squared. 3. The attempt at a solution Here is my attempt at the very first diagram (the 3.5 over all length) (2x1) + (2.5x3) = 9.5 Rb x 3.5 = 9.5 x 3.5 = 33.25 2+7 = Rb x 3.5 9.5/3.5 = 2.71KN Rb = 2.71KN ƩFup = ƩFdown Ra + Rb = 2 + 3 = 5 Ra + 2.71 = 5 - 2.71 = 2.5 KN Ra = 2.5KN So Rb = 2.71 KN and Ra = 2.5KN What i don't undertand is on my previous attempt, Ra = 2.286 KN and Rb = 2.714KN Where have i gone wrong? And what do i need to do after finding Ra and Rb?