physics word problem

Question

Is the force of friction the same for different angles of incline if all other parameters are equal? Explain by specifically used in the experiment. (the angles used were 30 and 45 degrees)

Answer 1

The frictional force is proportional to the normal force the incline exerts on the body. On an incline the normal force is dependent on the angle of the incline. The normal force is given by mass x g x cos(incline angle). The frictional force is F_r = μ x N where N is the normal force as given above and μ is the coefficient of friction.

As the can see the frictional force is dependent on the cosine of the incline angle and so is not the same for all angles of incline all else being equal.