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Slope and Deflection MCQs – Part 1

15 questions. Tap an option to check it instantly, then read the solution.

Practice SSC JE and other civil engineering exam questions on slope and deflection of beams: the differential equation of the elastic curve, double integration and Macaulay's method, boundary and symmetry conditions, Mohr's moment-area theorems, standard slope and deflection formulas for cantilevers and simply supported beams, superposition and compatibility problems, strain energy and Castigliano's theorem. Tap an option to check it, then open the full explanation for each question.

Question 1Hard
An overhanging beam ABC is pinned at A and on a roller at B (span AB = 6 m, overhang BC = 3 m) and carries a 10 kN downward point load at C. Macaulay's method gives EIy = −(5/6)x³ + C₁x + (5/2)[x − 6]³, with x measured from A (kN, m). Find the slope at A if EI = 10 × 10¹³ N·mm².
Full explanation

Answer: A. 0.0003 radian

y = 0 at B (x = 6): −(5/6)(216) + 6C₁ = 0 ⇒ C₁ = 30 kN·m². θA = C₁/EI = 30 × 10⁹ / (10 × 10¹³) = 0.0003 rad. (The original question printed C₁ as 0 and was cancelled.)

Question 2Easy
The integration constant C₁ used in Macaulay's method of analysis is obtained by applying ______ to the first integral (slope equation) of the differential equation of the elastic curve.
Full explanation

Answer: D. boundary condition for slope

First integration gives the slope equation with C₁, which is fixed by a known slope (e.g. dy/dx = 0 at a fixed end or at mid-span of a symmetric beam).

Question 3Easy
A cantilever ABC, fixed at A, carries downward point loads of 20 kN at B (2 m from A) and 10 kN at the free end C (1 m beyond B). EI is constant. The slope at the fixed end A is:
Full explanation

Answer: A. zero

A fixed support prevents rotation, so the slope at A is zero whatever the loads.

Question 4Easy
Which of the following methods used for finding the slope and deflection of beams is also called the 'method of singularity functions'?
Full explanation

Answer: A. Macaulay's method

Macaulay's method uses bracket (step) functions ⟨x − a⟩ that switch on at load points — these are singularity functions.

Question 5Medium
A cantilever AB of length l is fixed at A and carries a point load W at the free end B. Using the double integration method with x measured from the fixed end A, the slope dy/dx at any section is (EI = flexural rigidity):
Full explanation

Answer: C. dy/dx = −W(2lx − x²)/(2EI)

EI y'' = −W(l − x). Integrate: EI y' = −W(lx − x²/2) + C; y' = 0 at x = 0 ⇒ C = 0. So dy/dx = −W(2lx − x²)/(2EI).

Question 6Easy
For a cantilever AB (fixed at A) of length L carrying a point load P at the free end, the slope equation from the double integration method is EI dy/dx = −P(Lx − x²/2), with x measured from the fixed end. The maximum deflection is:
Full explanation

Answer: B. −PL³/(3EI)

EIy = −P(Lx²/2 − x³/6) + C; y = 0 at x = 0 ⇒ C = 0. At x = L: EIy = −P(L³/2 − L³/6) = −PL³/3.

Question 7Medium
A cantilever AB of length 5 m (fixed at A) carries a uniformly varying load whose intensity is 20 kN/m at the fixed end A and zero at the free end B. EI is constant. The slope at the free end is:
Full explanation

Answer: C. 104.16/EI

θB = wL³/(24EI) = 20 × 5³/(24EI) = 2500/24EI ≈ 104.17/EI.

Question 8Easy
The slope at the fixed support of a cantilever of length L and flexural rigidity EI, carrying a point load P at mid-span and another point load P at the free end, is:
Full explanation

Answer: D. zero

The fixed support prevents rotation, so the slope there is zero.

Question 9Medium
In the double integration method for a simply supported beam carrying a UDL over its entire span, the slope and deflection calculation requires:
Full explanation

Answer: A. the boundary condition as well as the symmetry condition

y = 0 at the supports (boundary condition) and dy/dx = 0 at mid-span (symmetry condition) give the two constants.

Question 10Easy
Which of the following is NOT a method for estimating deflections in beams?
Full explanation

Answer: C. Mohr's circle method

Mohr's circle finds normal and shear stresses on inclined planes; it has nothing to do with beam deflection.

Question 11Medium
A cantilever carrying a point load of 10 units at its free end has a maximum deflection of 1250/(3EI) units. The slope at its free end is:
Full explanation

Answer: C. 125/(EI) units

Pl³/3EI = 1250/3EI ⇒ 10l³ = 1250 ⇒ l = 5. Slope = Pl²/2EI = 10 × 25/2EI = 125/EI.

Question 12Easy
What is the deflection at the free end of a cantilever of length L carrying a point load P at its free end? (E = Young's modulus, I = moment of inertia)
Full explanation

Answer: D. PL³/(3EI)

Standard result: δ = PL³/3EI at the free end.

Question 13Easy
Which of the following methods is NOT used for finding the deflection of a beam?
Full explanation

Answer: D. Moment distribution method

The moment distribution (Hardy Cross) method finds support/joint moments in indeterminate structures, not deflections.

Question 14Hard
A cantilever of span l is fixed at one end, and its other end rests freely on the middle of a simply supported cross-beam of the same span and section. If the cantilever carries a UDL of w per unit length, the reaction at its free end offered by the cross-beam is:
Full explanation

Answer: B. 6wl/17

Compatibility: wl⁴/8EI − Rl³/3EI = Rl³/48EI ⇒ wl/8 = 17R/48 ⇒ R = 6wl/17.

Question 15Easy
A cantilever of span L carries a uniformly distributed load of w per unit length. The maximum deflection in the beam is (E = modulus of elasticity, I = moment of inertia):
Full explanation

Answer: A. wL⁴/(8EI)

Standard result: δmax = wL⁴/8EI at the free end.