Difficulty: Easy
Correct Answer: zero
Explanation:
Introduction:
Shear force and bending moment diagrams for basic loading cases are core knowledge in strength of materials. For a cantilever with a uniformly distributed load (UDL), recognizing boundary values helps draw accurate diagrams quickly.
Given Data / Assumptions:
Concept / Approach:
Shear force is the integral of load intensity, and the bending moment gradient equals shear. At the free end of a cantilever, there is no support reaction to carry shear; thus the internal shear at that section must be zero. Maximum shear occurs at the fixed support where reactions develop.
Step-by-Step Solution:
1) Resultant of UDL = w * l acting at midspan from the free end.2) Shear diagram for a cantilever with UDL starts at V = w * l at the fixed end and linearly decreases to V = 0 at the free end.3) Therefore, shear at the free end is zero.
Verification / Alternative check:
From boundary conditions, the free end cannot develop internal shear or moment; both must be zero at that free boundary.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing the fixed-end values (nonzero) with the free-end values (zero for both V and M).
Final Answer:
zero
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