Answer:
0.54
Explanation:
Energy is conserved, so the block's initial gravitational potential energy at the top of the incline is converted to kinetic energy at the bottom of the incline. That kinetic energy is then converted to work done by friction. On a level surface, the friction force is equal to the weight times the coefficient of friction.
PE = KE = W
mgh = Fd
mg L sin θ = mgμ d
L sin θ = μ d
μ = L sin θ / d
μ = 2.5 sin 40° / 3.00
μ = 0.54
