If the acceleration of the block in the diagram below is 5.00 m/s, what is the coefficient of kinetic friction?
20.0 kg
60.0°

Answer:
0.712
Explanation:
Forces are acting on the block according to the diagram attached , where
By definition
Fr = μ*R
= μ*mg *cos(60) ----------(1)
where μ -coefficient of kinetic friction
Applying F = ma along the incline (Assume g = 9.8 ms⁻²)
F = ma
mg * sin(60) - Fr = ma
mg*sin(60) - μ*mg *cos(60) = ma
9.8 * sin(60) - μ*9.8*cos(60) = 5
μ = 0.712