A 0.500 kg mass is attached to a spring of constant 150 N/m. A driving force F(t) = (3N)cos(ωt) is applied to the mass, and the damping coefficient b is 6.00 Ns/m. What is the amplitude (in cm) of the steady-state motion if ω is equal to half of the natural frequency ω0 of the system? Enter a number with two digits behind the decimal point.