Amplitude?5. Harmonic Motion with a Horizontal Spring

[adhoward24]

Homework Statement

A 215 g mass attached to a horizontal spring oscillates at a frequency of 5.20 hz. At t=0 s, the mass is at = 4.00 =cm and has velocity 26.0 cm/s. Determine the Amplitude.

Homework Equations

x(t)=ACos(2(pi)t)/T

The Attempt at a Solution

Well at t=o x=4, but then the 2(pi)t goes to zero and the whole equation equals 0. What am I doing wrong? Thanks for any and all help


And yes sorry units would help so there they are.

 

[cavalier]

Units would help. 215 grams? 5.20 Hz? 4.00 cm?

 

[blacknovember]

Sorry, new here.

1. Remember phase shift
2. Frequency...Angular frequency?
3. Consider two equations x(t) and v(t)
4. Solve...