A 0.38 kg mass is attached to a spring and executes simple harmonic motion with a period of 0.08 s. The total energy of the system is 1.9 J. Find: a) the force constant of the spring. Answer in units of N/m. b) the amplitude of the motion. Answer in units of m. For a, I got 2341.655 N/m by using the formula k= (T^2/4pi^2m) but how do I solve for b? And here is another question: A 1.02 kg mass is attached to a horizontal spring. The spring is initially stretched by 0.0478 m and the mass is released from rest there. After 0.507 s, the speed of the mass is zero (for the first time after being released). What is the maximum speed of the mass? Answer in units of m/s. I'm so lost in this questions because it is really confusing.