- #1

BryMan92

- 18

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## Homework Statement

See image.

## Homework Equations

ωx (ωx r) = anormal

αx r =atangent

x=rcos*theta

y=-rsin*theta

## The Attempt at a Solution

I solved for w=2 k rad/s and α= -1.5 k rad/s

I also got the correct answer using the cross products. My problem is I am trying to do this problem in rectangular coordinates (I really like rectangular), but I am doing something wrong and I cannot see it.

So, I assume r is constant:

x''=-r*cos(45)[ω^2-α] = Correct answer= -15.566

BUT, y'' is giving me a headache:

I keep getting rsin(45)[ω^2-α] and I get = 15.66 and NOT the right answer of 7.07 in/s. There is a lurking negative sign and I cannot find it. That - should be a + and then I get a correct answer. Am I just deriving incorrectly?

Thanks!

And apologizes if this is pretty novice: its from my Junior-level engineering class...or a freshman Physics class. ;p

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