Which one of the following statements is correct?

Explanation:

• The rate of change of shear force is equal to the load.

\({dV\over dx}=w\)

Where w = load per unit length.

• The rate of change of bending moment along the length of the beam is equal to the shear force.

\({dM\over dx}=V_x\)

Where V = shear force.

• The rate of change of bending moment changes abruptly at the location of the point load.
• At the hinge, the bending moment will be zero.
• The bending moment is maximum or minimum when the shear force is zero or change sign at a section.
• The point of contra-flexure/inflection is that point where the bending moment changes its sign.

Only statement (4) is correct. Hence option (4) is the correct answer.