A cantilever beam of 4 m span carries three point loads of 1 kN, 2 kN and 2 kN at 2 m, 3 m and 4 m from the fixed end respectively. What is the bending moment at 3 m from fixed support?

Concept:

Consider a cantilever of length l carries a concentrated load 'w' at its free end:

Taking moments about the section:

M = -Wx

The maximum bending moment occurs at the fixed end i.e. M = -WL

Calculation:

We have to find bending moment at C.

Let, B.M be M_x clockwise at C

So, Mx + 2 × (1) = 0

       Mx = –2 

Hence, bending moment will be 2 kNm anticlockwise.