# Homework Help: Velocity vector

1. Feb 24, 2014

### dawud

1. The problem statement, all variables and given/known data

It's attached.

2. Relevant equations

3. The attempt at a solution

I'm stuck on part b. I've attached my attempt at a solution not sure if it's right and, if it is, where to go from there.

#### Attached Files:

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• ###### sol.jpg
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2. Feb 24, 2014

### jackarms

All your work looks right so far. So now it looks like you have find times for the maximum and minimum of the speed, which will be a fairly straight-forward optimization problem.

3. Feb 24, 2014

### dawud

Thanks a lot btw. So I'm guessing I should differentiate the expression again right? And from there work out the max and min turning points of the graph?

4. Feb 24, 2014

### dawud

Oh man, I don't think this is working out for me lol. Here's the working I've done thus far, I don't think it's correct; any ideas where I went wrong?

Edit: I uploaded the attachments the wrong way round.

#### Attached Files:

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• ###### 2.jpg
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5. Feb 24, 2014

### jackarms

No, I think you're going the right way. The derivative does get a bit messy, but it helps that a and w are both constant, so you can throw those out. I think the answers you'll get will be fairly simple too.

6. Feb 24, 2014

### dawud

Since I've now got sin^-1(0) I don't know where to proceed from there. As far as I know, that wouldn't yield a max/min value, or would it? And I don't know how the w in the argument factors into all this

Last edited: Feb 24, 2014