Work out coefficient of friction instantly with clear inputs, formula shown and shareable results.
The coefficient of friction is the ratio of friction force to normal force, and being a ratio it is dimensionless. 45 N of resistance under a 150 N load gives 0.30. Its arctangent is the angle of friction, the slope at which the object would just begin to slide under its own weight.
Coefficient of friction
mu = F(friction) / F(normal)
Angle of friction
phi = arctan(mu)
For dry sliding, hardly at all. A wider contact spreads the same load over more area, so the pressure falls and the product stays roughly constant.
Tilt the surface to that angle and sliding starts. For mu = 0.3 that is about 16.7 degrees.