The frictional force is coefficient of friction times the normal reaction.
If ‘m’ is the mass of the object and ‘a’ is the angle of the plane, then the normal reaction is mg cos a.
The force that is pulling the object along the plane downward is mg sin a.
This is equal to the frictional force.
Therefore, mg sin a = (mu) mg cos a;
(mu) is the coefficient of friction.
Hence (mu) = tan a. We need not know the weight of the object.
This we can have as a formula for these cases of inclined plane.
Given 0.35 = tan a;
Hence a = 19.3 degree.
Tan a is opposite side / adjacent side of the inclined plane.
As long as "a" is constant the ratio will not change whatever is the length and height.
Use a calculator to find the tan inverse of 0.35.
Or check the value of tan 19.3 . you will get 0.35.
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