# Amplitude of oscillating spring

hopperd

## Homework Statement

a 185g mass attached to a horizontal spring oscilates at 5.2Hz. At t=0s, the amss is at x=5.80 and has a vx=-40.0cm. determine the amplitude

## The Attempt at a Solution

Homework Helper
welcome to pf!

hi hopperd! welcome to pf!

it's shm, so write a differential equation, and solve it with the given initial conditions …

what do you get?

hopperd
Thanks,
Thats the problem. I have tried 3 diff equations, and get the same answer, but it's the wrong one. So I must be missing something. What equation would you use?