The ANT 🐜 and The Coefficient of Static Friction Experiment (Class 11 Physics)

Calculating Frictional Force in Physics: Let us find the Coefficient of Static Friction experimentally or Mu Static between surface 1 that is iron a wooden box. We will use inclined plane physics (class 11) to calculate the Coefficient of Static Friction. We take the box and put it on an inclined plane made of iron and then slowly increase the incline. You you raise the angle to a point where the box just about starts sliding down.

Let's say that at this point the angle is alpha. Then the forces acting on the box are one, m*g acting in the downward direction. And if you resolve m*g into its component what you'll find is you'll get one force in this direction and another force would be in this direction .

In which case the vertical component of gravitational force would be m*g * cos(alpha) and vertical component would be m*g * sin(alpha). Since the box is not moving, there is a force of friction which is stopping its motion and it has to act in the opposite direction. This is the maximum static force of friction. If we apply Newton's second law of motion

m*g * sin(alpha) - Mu* N = ma
but we know that there is no acceleration because the object is stationary or it's just about to move.
mu_s * N = m*g * sin(alpha)

mu_s * m*g * cos(alpha) = m*g * sin(alpha).

The static coefficient of friction between two surfaces is the tan of the angle at which the object just about starts moving. The coefficient of static friction is independent of the mass. So it's dependent on the nature of the two surfaces only.

So this Experiment that uses an Inclined Plane Physics is widely used to find the coefficient of static Friction for various surfaces. Friction on Inclined plane also appears in several Class 11 inclined plane physics problems. This lesson would be helpful for such physics numerical problems

[Dr.TegfatehSingh]

I could be wrong, but I think that graph would only be derived if the acceleration produced by the force is constant?