The normal force of the force given is calculated through the equation,
Fn = F(sin θ)
where Fn is the normal force, F is the force, and θ is the angle.
Fn = (25 N)(sin 60°) = 21.65 N
The x-component of the force applied is,
Fx = (25 N)(cos 60°) = 12.5 N
The value of the coefficient of static friction is calculated through the equation,
F = μFn
μ = Fx / Fn = 12.5 N / 21.65 N = 0.577