ME 203 Homework

Summer 2015

On problem number 2, are there supposed to be angle values, or are we to provide a solution in symbolic form?
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And it begins... Homework 01

Lyric of the day
I felt a little fear upon my back
He said “Don’t look back, just keep on walking.”

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This was posted earlier...

For problem number three on the hw, once you have plotted the position, velocity and acceleration functions using matlab how would you identify the value of time at which the ball hits the ground on the graph at y=0? I don’t understand how to interact with the matlab graph when it comes to pulling data from the graph. When I plotted the function on my calculator, I was able to get t=4.106s at y=0.

I would just do the same with MATLAB. Plot the function and then visually find when the graph crossed y = 0.

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Really? Already? Yep... it’s Homework 02

Lyric of the day
Ten thousand cars by the side of the road
Grooving far as the eye can see.

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It’s not easy being green... Fortunately Homework 02 is not green.

Lyric of the day
And the three men I admire most
The Father Son and Holy Ghost
They caught the last train for the coast
The day the music died.

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Fireworks... and Homework 05.

Lyric of the day
See the man with the lonely eyes
Take his hand, you’ll be surprised.

In problem 2, what do the white bars that go through the pulleys mean? Do they mean that those pulleys are fixed in an imaginary wall (if there was such)?
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The white bars are just there to emphasize that the pulley moves along with the rope. Also, in problem 3 the magnitude is the amplitude of the acceleration, a scalar value, and can be determined using the Pythagorean theorem.
Along with that, Since we know that the two sides of a pulley = 2 times the center (Va + Vb = 2Vc) What, if anything, would it change in that equation if that rope running through the center is connected to the center?
On problem number 3, what exactly do you want for the magnitude of the acceleration? Do I just use the Pythagorean theorem to find the magnitude, or just leave the answer in terms of er and etheta?

In problem 1, should we assume that the top of the pulley is right at the ceiling to find the position of the collar with respect to the pulley?
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Yes, and that the pulley has an infinitesimally small radius.
For problem 2, do we have to use the law of sines to determine the angle at point P. If not, how do we relate the motion of AB to BP?

For the first question, why can we assume that there is only acceleration in the i direction? If the front wheels lift off the ground, there wouldn’t be acceleration in the j direction?
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There would, but in this case you would want to solve the problem when it stays on the ground, and then look for when the normal force becomes adhesive (holding the wheels to the ground).