A shear force diagram is a right-angled triangle: zero at the free (right) end and rising linearly to wl at the fixed (left) support. It belongs to:
Try it first: pick an option, then read the explanation.
Asked in SSC JE 04/03/2017 (Morning)
Detailed Explanation
A linearly varying SFD means a constant load intensity (dV/dx = w). Zero at one end and maximum at the other, with only one support, means a cantilever.
Why “a cantilever with a uniformly distributed load” Is Correct
A SS beam with UDL would give a line from +wl/2 to −wl/2; a cantilever with an end load would give a rectangle. Only a cantilever with a UDL gives a triangle from 0 to wl — option (d).
Why the Other Options Are Wrong
- A. a simply supported beam with an isolated central load: A central load on a SS beam gives two rectangles (+W/2 and −W/2).
- B. a simply supported beam with a uniformly distributed load: A SS beam with UDL gives a line crossing zero at mid-span.
- C. a cantilever with an isolated load at the free end: An end load on a cantilever gives a rectangle of height W.
Key Point
Cantilever + UDL: triangular SFD (0 → wl), parabolic BMD (0 → wl²/2).
Key Concepts for Students
- Shape of SFD identifies the loading: rectangle = point loads, triangle = UDL.
- The steepness of the SFD equals the load intensity.
- A triangular load would give a curved (parabolic) SFD.
Practice more: this is question 47 in Bending Moment and Shear Force MCQs – Part 4. Try the whole set and check every answer instantly.