EIT Statics and Dynamics 2 — Questions and Answers
Question 1: What is the moment of inertia of a solid cylinder (mass M, radius R) about its central axis?
- MR²
- ½MR² (Correct answer)
- ⅔MR²
- 2MR²
Correct answer: ½MR²
The moment of inertia of a solid cylinder about its axis of symmetry is I = ½MR².
Question 2: In projectile motion (neglecting air resistance), which component of velocity remains constant?
- Vertical component
- Horizontal component (Correct answer)
- Both components
- Neither component
Correct answer: Horizontal component
With no air resistance, only gravity acts, and it acts vertically — so the horizontal velocity component remains constant throughout.
Question 3: The coefficient of restitution e = 1 describes:
- A perfectly plastic collision
- A partially elastic collision
- A perfectly elastic collision (Correct answer)
- An explosive collision
Correct answer: A perfectly elastic collision
A coefficient of restitution of 1 indicates a perfectly elastic collision where kinetic energy is fully conserved.
Question 4: For a free-body diagram, which of the following should be included?
- Only applied external forces
- All forces including internal forces
- All external forces and moments acting on the body (Correct answer)
- Only gravity and normal force
Correct answer: All external forces and moments acting on the body
A free-body diagram includes all external forces and moments acting on the isolated body, revealing what affects its motion.
Question 5: What is the angular momentum of a 2 kg mass rotating at 5 rad/s with a radius of 0.4 m?
- 4 kg·m²/s
- 1.6 kg·m²/s (Correct answer)
- 10 kg·m²/s
- 8 kg·m²/s
Correct answer: 1.6 kg·m²/s
L = Iω = mr²ω = 2 × (0.4)² × 5 = 2 × 0.16 × 5 = 1.6 kg·m²/s.
Question 6: A truss member in compression will fail by which mechanism at long lengths?
- Tensile fracture
- Shear failure
- Euler buckling (Correct answer)
- Plastic deformation
Correct answer: Euler buckling
Slender compression members fail by Euler buckling — a sudden lateral deflection — before reaching the material's yield stress.
EIT Statics and Dynamics 2
What is the moment of inertia of a solid cylinder (mass M, radius R) about its central axis?