Difficulty: Easy
Correct Answer: None of the above (it is always true for the free end of a cantilever)
Explanation:
Introduction / Context:
Cantilever beams are fixed at one end and free at the other. Understanding boundary conditions—especially that the free end cannot transmit moment or shear—is crucial for drawing correct shear-force and bending-moment diagrams.
Given Data / Assumptions:
Concept / Approach:
By definition, at the free end of a cantilever, there is no support to develop a reaction shear or reaction moment. Therefore, the internal shear force V and bending moment M evaluated at the very free tip are zero for any applied loading configuration.
Step-by-Step Solution:
Verification / Alternative check:
All standard shear and moment diagrams for cantilevers start at zero at the free end and grow towards the fixed end to meet boundary conditions at the built-in support.
Why Other Options Are Wrong:
Options limiting the zero condition to particular loads (point load or UDL) are incorrect; the zero condition holds universally at the free end.“True only for no loading” is false; even with loads, the free-end values remain zero.
Common Pitfalls:
Misreading internal shear/moment at a small distance from the tip (which may be nonzero) versus exactly at the tip where both are zero.
Final Answer:
None of the above (it is always true for the free end of a cantilever)
Discussion & Comments