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A 2 kg block is pulled with uniform speed up a plane which makes 30 degrees with the horizontal by a force of 15 N
which is parallel to the plane. Find the coefficient of kinetic friction between the block and the plane.
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Since the block is pulled uniformly up the plane, it means that the force of 15 N parallel to the plane
is equal to the sum of the rolling force and the friction force.
The rolling force R parallel to the inclined plane is R = m*g*sin(30°) = 2*10*(1/2) = 10 newtons.
The normal reaction force N, which is PERPENDICULAR to the inclined plane, has the value of
N = m*g*cos(30°) = = = 17.32 newtons.
The friction force is equal to = k*N = 17.32*k, where "k" is the kinematic friction coefficient.
So we have this equation to find out the kinetic friction coefficient
15 = R + = 10 + 17.32k.
From the equation, we find
k = = 0.287 (the dimensionless value).
ANSWER. Under given condition, the kinetic friction coefficient value is 0.287.
Solved.