# Finding amplitude

1. Jan 7, 2010

### zachmgilbert

1. The problem statement, all variables and given/known data
what is the amplitude of the motion v=-6.54sin(20.1t) (mks units)
angular frequency=20.1

2. Relevant equations
v=wAcoswt

3. The attempt at a solution
I think the wavelength is 6.54 since 20.1 is the frequency. v =6.2 m/s. I am missing time.

2. Jan 7, 2010

### zachmgilbert

update: i used T=1/f to find time, divided by four because thats when the displacement will be maximum plugged all this in and got .32, the correct answer I know is .33. I didn't round to the end so I feel like this is luck and not the correct way, am i making this too difficult?

3. Jan 7, 2010

### rock.freak667

If you know v is in the form v=-ωAsin(ωt) = -6.54sin(20.1t), then shouldn't ωA=6.54 and you know ω=20.1

4. Jan 7, 2010

### zachmgilbert

You are correct. I thought v=-6.54sin(20.1t) was a form of v=λf and I couldn't figure out where the sin and t came from. Thank you for helping me with a stupid mistake.