# Vibrations & waves please Help

1. Apr 28, 2006

### chazgurl4life

A 0.55 kg mass at the end of a spring vibrates 2.0 times per second with an amplitude of 0.16 m.
(a) Determine the velocity when it passes the equilibrium point.
I have no idea how to figure this out

i mean to figure out velocity ...we use this equstion vmax= 2pi*Amplitude* Frequency

I ahve the amplitude but no frequency..im i using the right process???

2. Apr 28, 2006

### Staff: Mentor

How is the frequency of oscillation related to the spring constant k? What else determines the frequency of oscillation? Once you have k, do you have what you need to figure out the midpoint velocity? You can also do it with energy conservation (KE + PE = constant)....

3. Apr 28, 2006

### chazgurl4life

Ok so i know that K= (2pi*freq.)^2* mass and then once i have K i can uses vmax= 2pi Af and solve for A?

4. Apr 28, 2006

### Staff: Mentor

I thought you had the amplitude and frequency already. What is the SHM equation for the motion of the object in terms of the mass, spring constant k, amplitude and frequency?

y(t) = something * sin( something * t )

And then you can get the velocity by differentiating, right? Or else just take the easy way out and use the conservation of energy method that I mentioned.

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