Fundamentals of Engineering Statics and Dynamics 1 — Questions and Answers
Question 1: For a body to be in static equilibrium, the sum of all forces and the sum of all moments must each equal:
- Zero (Correct answer)
- A constant
- The weight of the body
- The reaction force
Correct answer: Zero
Static equilibrium requires ΣF = 0 (force equilibrium) and ΣM = 0 (moment equilibrium) simultaneously.
Question 2: A simply supported beam of length 10 m carries a 50 kN load at mid-span. What is each reaction force?
- 25 kN (Correct answer)
- 50 kN
- 10 kN
- 5 kN
Correct answer: 25 kN
By symmetry, each support carries half the load: 50/2 = 25 kN.
Question 3: The moment of a force about a point equals:
- Force times perpendicular distance from the point to the line of action (Correct answer)
- Force times the length of the beam
- Force divided by distance
- Force times angle
Correct answer: Force times perpendicular distance from the point to the line of action
Moment M = F × d, where d is the perpendicular distance (moment arm) from the point to the line of action.
Question 4: What is the formula for Newton's second law in dynamics?
- ΣF = ma (Correct answer)
- ΣF = mv
- ΣF = m/a
- ΣF = mv²
Correct answer: ΣF = ma
Newton's second law states that the net force equals mass times acceleration: ΣF = ma.
Question 5: What is the centroid location (ȳ) of a rectangle with height h measured from its base?
- h/2 (Correct answer)
- h/3
- h/4
- 2h/3
Correct answer: h/2
The centroid of a rectangle is at its geometric center, which is h/2 from any edge.
Question 6: Which theorem relates the moment of inertia about an axis through the centroid to that about a parallel axis?
- Parallel axis theorem (Correct answer)
- Perpendicular axis theorem
- Green's theorem
- Varignon's theorem
Correct answer: Parallel axis theorem
The parallel axis theorem states I = Iₐ + Ad², where Iₐ is the centroidal moment of inertia and d is the distance between axes.
Fundamentals of Engineering Statics and Dynamics 1
For a body to be in static equilibrium, the sum of all forces and the sum of all moments must each equal: