Physics
posted by Elle on .
A 4.07 x 102kg block is resting on a horizontal frictionless surface and is attached to a horizontal spring whose spring constant is 144 N/m. The block is shoved parallel to the spring axis and is given an initial speed of 10.5 m/s, while the spring is initially unstrained. What is the amplitude of the resulting simple harmonic motion?

well, the initial KE= 1/2 m v^2 which is given. At full extension, the PE stored is 1/2 k x^2
x is the amplitude, solve for it.