Answer (1 of 2): EDIT 2020-09-14 Without explaining all the calculus to prove it, a simple rule of thumb is: 1. the change in shear = -(area under the load curve (w)) 2. slope of the V curve = -(w) 3. slope of the M curve = V 4. the change in M = area under the V curve. Here's how I got my numb...