3D Static Friction on an Inclined Plane
This 3D simulation demonstrates how the coefficient of static friction (μs) can be determined by finding the angle at which a block just begins to slide.
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Weight (mg)
Normal Force (N)
Friction Force (fs)
Components of Weight
Physics Explanation:
When a block rests on an inclined plane, three forces act on it:
- Weight (mg) acting vertically downward
- Normal force (N) perpendicular to the plane
- Static friction (fs) parallel to the plane opposing motion
We can resolve the weight into two components:
mg sinθ (parallel to plane) and mg cosθ (perpendicular to plane)
At equilibrium, just before sliding begins:
fs = μsN = mg sinθ
N = mg cosθ
Therefore: μs = tanθmax
N = mg cosθ
Therefore: μs = tanθmax
In this example from the textbook:
θmax = 15° ⇒ μs = tan(15°) ≈ 0.27
