What is the amplitude of oscillation?

An object with mass 0.200 kg is acted on by an elastic restoring force with force constant 10.0 N/m. 
(a) Graph elastic potential energy U as a function of displacement x over a range of x from - 0.300 m to +0.300 m. On your graph, let 1 cm = 0.05 J vertically and 1 cm = 0.05 m horizontally the object is set into oscillation with an initial potential energy of 0.140 J and an initial kinetic energy of 0.060 J. Answer the following questions by referring to the graph. 
(b) What is the amplitude of oscillation? 
(c) What is the potential energy when the displacement is one-half the amplitude? 
(d) At what displacement are the kinetic and potential energies equal? 
(e) What is the value of the phase angle'" if the initial velocity is positive and the initial displacement is negative?