Find Frequency and Amplitude from Max Velocity and Accn

[rocapp]

Homework Statement

See attached screenshot

Homework Equations

Vmax=Aω
a_y=-ω²A

The Attempt at a Solution

The given max velocity is 1.2 m/s, so

1.2 = ωA

Ay = -ω^2A

1.2/A = -√260/A
A = 0.005

 

[haruspex]

1.2/A = -√260/A

Parentheses would help, and don't worry about the sign because you only want the magnitude.

A = 0.005

A little inaccurate. How many significant figures do you think you should provide?
This is just part B. Any problem with part A?

 

[rocapp]

I tried 0.006, but it didn't work either. I am not sure what to do for part A at all.

 

[haruspex]

I tried 0.006, but it didn't work either.

You didn't answer my other question: how many significant figure do you think you should give in the answer? Why are you only giving one?

I am not sure what to do for part A at all.

You already have an equation you can solve for ω.

 

[rocapp]

There should be two significant figures, but my homework doesn't mind a little inaccuracy. I'm still having difficulty with part A.

Since

A = (ω)/(vmax)

and

A = (amax)/(ω²)

then

ω/vmax = amax/(ω²)

Plug in knowns:

260/(ω^2) = ω/1.2
ω³ = 312
ω = 6.78
ω = 2πf
f = 1.08

This is not correct, though. And I do not know why.

 

[haruspex]

There should be two significant figures, but my homework doesn't mind a little inaccuracy. I'm still having difficulty with part A.

OK, but I think it's worth trying 0.0055

Since A = (ω)/(vmax)

No - try that one again. (What dimension would frequency/speed have?)

 

[rocapp]

0.0055 was incorrect.

frequency/speed would be m/sec^2... OH!

So A = (vmax)/ω, correct?

 

[haruspex]

0.0055 was incorrect.

frequency/speed would be m/sec^2... OH!

So A = (vmax)/ω, correct?

Yes.

 

[rocapp]

I'm still getting 0.0055 for amplitude. Any ideas?

 

[haruspex]

0.0055m looks right to me.

 

[rocapp]

Well the homework software is counting it wrong. Thanks for the help!