Civil Engineering Orientation2D
Civil Engineering Education - Examples & Applications - Forces Equilibrium
Apply prerequisite thinking, outcomes-based education, laboratory evidence, mechanics, verification, and professional responsibility to civil engineering study.
Open the complete lessonSupplemental mechanics lab
Equilibrium, Static Friction, and Sliding
Increase the horizontal applied force and observe the transition from static equilibrium to sliding on an ideal horizontal surface.
Model assumptions: horizontal rigid surface, no vertical applied-force component, constant coefficients, and μk ≤ μs. Real contact behavior can be more complex.
Current state
Static equilibrium
Static friction adjusts to match the applied force, up to its limiting value, so the horizontal net force remains zero.
- Weight W
- 490.5 N
- Normal N
- 490.5 N
- Max static friction
- 196.2 N
- Actual friction
- 120.0 N
- Horizontal net force
- 0.0 N
- Acceleration
- 0.00 m/s²
W = mg = 50 × 9.81 = 490.5 N
fₛ,max = μₛN = 0.40 × 490.5 = 196.2 N
fₛ = P = 120.0 N while P ≤ fₛ,max