A 2 kg mass is attached to a spring with spring constant = 200 N/m. After stretching the spring by 4 cm and then releasing, the amplitude (value of x) at t = 1.333 sec is x = -.951 cm. A) Determine the initial phase, Φ, and B) write the equation the equation of motion in the form x(t) = A cos (kx + Φ)