Solve this multiple-choice question and choose the correct option.

Home » Mechanical Engineering » Strength of Materials

Beam theory: meaning of point of contraflexure (inflection point) On a bending moment diagram for a beam, identify what occurs at the point of contraflexure.

Difficulty: Easy

Shear force changes sign
Bending moment changes sign (passes through zero)
Shear force is maximum
Bending moment is maximum

Correct Answer: Bending moment changes sign (passes through zero)

Explanation:

ConceptThe point of contraflexure (inflection) is where the curvature changes sign; equivalently, the bending moment diagram crosses zero.

Final AnswerBending moment changes sign (passes through zero).

← Previous Question Next Question→

More Questions from Strength of Materials

Solid circular shaft: torque–diameter relation at allowable shear stress For a solid circular shaft of diameter D, limited by maximum allowable shear stress τ, state the formula for the maximum torque transmitted.
Stability of columns: applicability of Euler's buckling formula State for which type of column Euler's critical load formula is valid, based on slenderness.
Plane stress analysis: compute the maximum normal stress (principal stress) for a biaxial state with shear A body is under σ_x = 1200 MPa (tension) and σ_y = 600 MPa (tension) on mutually perpendicular planes. A shear stress τ_xy = 400 MPa acts on the same planes. Determine the maximum principal (normal) stress.
Thick cylinder (Lame’s theory): Maximum tangential (hoop) stress at the inner surface due to internal pressure. Given: a thick cylindrical shell with inner radius r_i, outer radius r_o, internal pressure p, and negligible external pressure. Choose the correct expression for the maximum hoop stress at r = r_i.
Composite torsional shaft: Equivalent torsional spring constant for two serial segments between rigid ends. Given two stepped portions with torsional spring constants k₁ and k₂ in series (same torque, angular twists add). Choose the correct expression for the equivalent spring constant k_eq.
Strength of materials—bars under self-weight: What is the ratio of the elongation of a conical bar due to its own weight to that of a prismatic bar of the same material and length (both hanging vertically)?
Power transmission design: The maximum twisting moment a circular shaft can safely resist equals the permissible shear stress multiplied by which geometric property?
For a cantilever beam of length L subjected to a pure couple M applied at the free end, what is the vertical deflection at the free end in terms of E and I?
Riveted joints: For a diamond riveting pattern in a plate, the weakest net section typically passes through which row of rivet holes?
In structural analysis using the transformed section method, a reinforced concrete (R.C.) beam is treated as which of the following for the purpose of flexural analysis?

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion