The full question is: A 4.10 kg object on a horizontal frictionless surface is attached to a spring with spring constant 900 N/m. The object is displaced from equilibrium 50.0 cm horizontally (in the direction) and given an initial velocity of 10.1 m/s back toward the equilibrium point at t=0 s.
(a) What is the frequency of the motion?
(b) What is the initial potential energy of the block-spring system?
(c) What is the initial kinetic energy?
(d) What is the amplitude of the oscillation?
(e) Write down the equation: Please fill in the numerical values for A, ? and below, in SI units. Use a positive value.
x(t) = ? · cos ( ? · t + ? )
(f) What is the smallest possible NEGATIVE phase angle that could be used to describe this motion?