An air-track glider attached to a spring oscillates with a period of 2.70 s . At t = 0 the glider is 5.10 cm left of the equilibrium position and moving to the right at 13.7 cm/s .

a.) Assume that the simple harmonic motion of the glider will be written as an amplitude times a cosine function with a phase constant. Take rightward on the glider track to be the positive direction and leftward to be the negative direction. What is the phase constant in radians and in degrees? Give your answers as an ordered pair, with the phase constant in radians (between and +) first, followed by a comma, followed by the phase constant in degrees (between 180 and 180).

b.) What is the amplitude of the motion? Give your answer in cm.