Quiz 9 Solutions

More quiz solutions are coming, but this one is obviously most time sensitive.

I would like to mention a few things:

1. Regarding fluid force. I believe I neglected to note that, while Force = pressure * Area, pressure is rho*g*depth. So be aware that there is a g there. I think I neglected this in class.

2. Remember that My is associated with x, and Mx is associated with y. They switch. This is important as the formulas for x-bar and y-bar are not given on the exam.

Also, we should note that e^0 is 1, not 0. e^x never equals zero for any x.

m172 quiz 9 solution

Extra credit quiz solutions

Hi all, here are the extra credit quiz solutions. Sorry it took me a bit to crank through and make these solutions.

The optimization problem is quite a bit more computationally rigorous than many things we have done, but it is doable. Honestly, I meant to change the problem number on that one, but ended up not rendering the final changes… Sorry. But hey! Algebra practice! It builds character. Or that’s what math professors claim to tell you when they screw up 😉

You need to take special care with your interval. Since when you differentiate, you get stuff in the denominator, before you can multiply through to 0, I must ensure that I did not divide by zero. That was how I determined what the interval was. Once you get the denominator, it is at least straightforward to find the correct r. You can then plug this r back into your original constraint to find h, but time was short and so was my sheet of paper.

extra credit quiz soln pg 1

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extra credit quiz soln pg 3