STRENGTH OF MATERIAL MCQ SET 7
Q1. The torsional equation is:
A) T/J = ฯ/R = Gฮธ/L
B) T/J = ฯ/y
C) M/I = f/y
D) ฯ = Gฮธ
Answer: A) T/J = ฯ/R = Gฮธ/L
Explanation: This is the fundamental torsion equation used in circular shafts.
Q2. The maximum shear stress in a solid circular shaft occurs at:
A) Axis of shaft
B) Outer surface
C) Middle
D) Neutral layer
Answer: B) Outer surface
Explanation: Shear stress increases from zero at the center to maximum at the outer surface.
Q3. The polar moment of inertia for a solid circular shaft of diameter D is:
A) ฯDยณ/16
B) ฯDโด/32
C) ฯDโด/64
D) ฯDโด/8
Answer: B) ฯDโด/32
Explanation: Polar moment of inertia J = ฯDโด/32 for a solid circular cross-section.
Q4. In torsion, the angle of twist is directly proportional to:
A) Length of shaft
B) Modulus of rigidity
C) Polar moment of inertia
D) Diameter of shaft
Answer: A) Length of shaft
Explanation: ฮธ = (TL)/(JG), so longer shafts twist more under same torque.
Q5. The strain energy stored in a shaft under torsion is called:
A) Resilience
B) Torsional energy
C) Shear strain energy
D) Twisting energy
Answer: C) Shear strain energy
Explanation: It is the energy stored due to shear stress in torsion.
Q6. The term โspring indexโ is defined as:
A) Mean coil diameter / Wire diameter
B) Wire diameter / Mean coil diameter
C) Number of turns / Pitch
D) Pitch / Number of turns
Answer: A) Mean coil diameter / Wire diameter
Explanation: Spring index (C) = D/d, it affects the stiffness and stress in springs.
Q7. The stiffness of a spring is the ratio of:
A) Load to deflection
B) Deflection to load
C) Load to number of turns
D) Wire diameter to mean coil diameter
Answer: A) Load to deflection
Explanation: Stiffness (k) = W/ฮด, representing the resistance to deformation.
Q8. The modulus of rigidity (G) for steel is approximately:
A) 80 GPa
B) 200 GPa
C) 100 GPa
D) 160 GPa
Answer: A) 80 GPa
Explanation: For steel, G โ 80 ร 10โน N/mยฒ.
Q9. The deflection of a cantilever beam with a point load at free end is given by:
A) WLยณ/3EI
B) WLยณ/8EI
C) WLยณ/48EI
D) WLยณ/2EI
Answer: A) WLยณ/3EI
Explanation: Formula for deflection ฮด = WLยณ / (3EI).
Q10. The deflection in a simply supported beam under central load is:
A) WLยณ/8EI
B) WLยณ/48EI
C) WLยณ/16EI
D) WLยณ/12EI
Answer: B) WLยณ/48EI
Explanation: ฮด = WLยณ / (48EI) for simply supported beam under central load.
Leave a Reply