For the overhanging beam in the figure, A) draw the moment diagram indicating all critical values including the maximum moment (Value and location), and B) write the moment function, M(x), for B-C section in terms of x coordinate as shown in the figure.
F = ma
M = F*d
(1/3x) <---- (Equation for the slope of the triangular load from B-C I think)
-1/6x^2 <---- (Equation for the slope of the shear load from B-C I think)
-1/18x^3 <---- (Equation for the slope of the moment diagram from B-C I think)
The Attempt at a Solution
Mc = -Ra(10) + (20)(6) + 1/2(6)(2)(1/3(6)) - (2)(4)(2) = 0 therefore, Ra = 11.6 kips
Fy = Ra - 20 - 1/2(6)(2) - 2(4) + Rc = 0 therefore, Rc = 22.4 kips
I'm trying to figure out how to find where the middle cubic function crosses the x-axis and I'm having a really hard time. Could I get a push in the right direction please?