EIT Statics and Dynamics 1 — Questions and Answers
Question 1: For a body in static equilibrium, the sum of all forces must equal:
- Maximum force
- Minimum force
- Zero (Correct answer)
- Body weight
Correct answer: Zero
Static equilibrium requires ΣF = 0 (net force) and ΣM = 0 (net moment), meaning all forces and moments balance.
Question 2: The moment of a force about a point is calculated as:
- Force × distance along the force direction
- Force × perpendicular distance from the point to the line of action (Correct answer)
- Force / distance
- Force² × distance
Correct answer: Force × perpendicular distance from the point to the line of action
Moment (torque) M = F × d, where d is the perpendicular distance from the pivot to the line of action of the force.
Question 3: What is the centroid location of a uniform rectangular plate with width w and height h?
- At the corner
- At w/3 from one edge and h/3 from the bottom
- At the center (w/2, h/2) (Correct answer)
- At the top edge
Correct answer: At the center (w/2, h/2)
For a uniform rectangle, the centroid is at the geometric center, at distances w/2 and h/2 from each respective side.
Question 4: Newton's second law for a particle states:
- F = mv
- F = ma (Correct answer)
- F = m/a
- F = v × a
Correct answer: F = ma
Newton's second law: net force F = ma, where m is mass and a is acceleration.
Question 5: A 500N block rests on a horizontal surface with μ_s = 0.4. What is the maximum static friction force?
- 125 N
- 200 N (Correct answer)
- 500 N
- 2000 N
Correct answer: 200 N
Maximum static friction f_s = μ_s × N = 0.4 × 500 = 200 N.
Question 6: The principle of work-energy theorem states that net work done on a particle equals:
- Change in potential energy
- Change in kinetic energy (Correct answer)
- Total mechanical energy
- Product of force and time
Correct answer: Change in kinetic energy
The work-energy theorem states W_net = ΔKE = ½mv₂² - ½mv₁², relating net work to the change in kinetic energy.
EIT Statics and Dynamics 1
For a body in static equilibrium, the sum of all forces must equal: