Lame Saturday Night Activities: How Bad Is It?

[mmpsteve]

I agree, that's not lame. It's created memories that should last a lifetime.

Not only will it last a lifetime, but it will probably influence several lifetimes.

Congratulations, Sir. Well done.

p.s. To the thread topic, I spent the last two Saturday nights (or was it Sunday?) watching Lawrence Welk with my 90 year old parents. Great time had by all, and memories I'll cherish.

 

[91FXRS]

With school in session we have a limited number of nights for the terrorists (avatar) and their 11 year old sister. In this w have a sleep over on Saturday night with the 3 of them. It is and a movie time for us. Especially as the fall/winter months close in. They pick the movie. I put up the air mattress and they make the ........Lame...maybe but this is a special time with them. Well worth the time spent. Before I know it this will not be the activity of choice on a Saturday night anymore.

What you are doing is creating the perfect Saturday night for three angles that will never forget such wonderful times.

 

[rhino]

So . . .

Before I started on my homework due on Sunday night, I decided to complete the discussion board assignment that is also due on Sunday. We had a choice of four questions to answer/discuss, so I took the option at the top of the list, "Discuss velocity and net change and their applications." The instructions indicated a 75 word minimum.

So I started typing and when I stopped to check for any obvious typos, I was at 662 words, and I was just getting on a roll! The instructor suggested that I aim for a word count closer to the requirement next time.

I blame the engineering degrees and teaching physics for 6 years.

Discuss velocity and net change and their applications

Discussing velocity and net change and their applications is a broad topic, so I will pick a few ideas to share here.


Isaac Newton developed differential calculus specifically to help him describe the physics of motion, from simple moving objects he could observe on Earth to the motion of the planets. Motion can be described by three very closely related quantities: displacement, velocity, and acceleration. The relationship among the the three is best described using the idea of the derivative and the integral.


Displacement is the simplest of the three. It is just the magnitude and direction of how far a body has moved from some point of reference, often the origin on a 2-D or 3-D coordinate plane. It is essentially the net change in position.


Velocity is the both the rate at which displacement is changing as well as the direction of the change. Velocity is the net change in displacement per unit of time it took to make the change. Velocity can be an average, computed using the total displacement divided by the total time, which in calculus corresponds to the slope a secant line through two points on the displacement curve. Velocity can also be an instantaneous value, or the value at a specific point in time, which is determined by the rate at which the displacement curve is changing at a specific point. Geometrically, this is the slope of the tangent line to the displacement curve, for which we use the term derivative in calculus.


Acceleration in a physical sense is any change in an object's state of motion, whether it's a change in magnitude of the velocity or a change in direction, or both. So acceleration is the net change in velocity per unit of time. The relationship between velocity and acceleration is analogous to the relationship between displacement and velocity. The rate of change of velocity (including direction) is the acceleration. So the acceleration is then the derivative of the velocity, or the second derivative of the displacement.


That means that if you have a relationship (formula) for the displacement, you already know the velocity and acceleration simply by differentiating twice. The reverse is also true, in that if you know the acceleration, you can then find the velocity by finding the antiderivative (i.e. integrating) and then again to determine the displacement. However, we can't overlook that when you integrate an indefinite integral, you will have constant in addition to the antiderivative. Never fear! The constants of integration are evaluated using what are known as initial values, which are typically a value for the velocity and the displacement at a given time (usually t=0). With that, you know all you need to know to describe the motion of a body in Newtonian terms.


Application of this idea are numerous! The simplest are presented in physics courses as falling bodies and the motion of projectiles. In most cases, some physical parameters are considered constant (such as the acceleration due to gravity in a given region) or are initially neglected (such as the effects of wind resistance) for simplicity. We know that the acceleration due to gravity varies based on position, but for most simple problems, it is reasonable to assume that it is constant. In those cases, many problems can be solved using a few simple classic formulas and a little algebra.


The beauty of having the tools of the derivative and the integral at your command is that you are not limited to situations where the formulas are given to you, nor are you stymied if the acceleration is presented as a non-constant expression. Knowing the simple relationship between the three (in terms of derivatives/integrals) and an expression for one (and probably some initial conditions), you can determine the rest.


I've only scratched the surface of this discussion, but I'm well past the 75 word minimum and there is plenty to discuss about what I wrote above!

 

[rhino]

Note to self:

Calculating surface areas of solids formed by revolving a curve about the x-axis or the y-axis is tricky and tedious, especially when you have to convert everything expressed in terms of x to y, including the limits of integration, and then integrate using a substitution, which also requires converting limits of integration again.

I do not like it and the opportunity of small error during each step are many.

 

[rhino]

I'm officially regretting taking Calculus II now. Calculus I took some time to do all the work since it was condensed into 8 weeks for the summer term, but there were few concepts that were conceptually difficult for me or techniques difficult to learn and demonstrate on demand. I'm having a harder time now. The homework sets are shorter, but they're taking a lot longer to complete. Part is that the materials is a bit rustier in my brain, but I also think that the instructor for this course has specifically chosen to make it more difficult (in terms of problem selection) than the instructor I had in the summer. Another factor is that I have additional stress now that I did not have over the summer.

I'm not going to quit, but while the work for Calculus I was almost fun, the same cannot be said for Calculus II. The fun is gone, baby . . . gone.

So . . . tonight I had trouble getting an expression for the Surface Area to Volume ratio of an ellipsoid (a 3-D solid formed by rotating an ellipse around one of the coordinate axes). As part of the problem statement, we were given an expression for the surface area in terms of the long axis and one of the short axes (the two short axes are equal) and a confusing expression for the volume and I was unable to combine the two and get an expression for the SAV in the specified form.

The homework system is set to allow us to repeat a problem one additional time if we get it wrong. In most cases, the second try is similar, but with different values and parameters. However, in this case the second try was identical to the first, so I was able to enter the correct answer for credit. However, that does me little good because I don't know how to get that answer!

I sent a message to the instructor asking for a solution or for a pointer to a solution. However, when this happened in the past when I was able to get the correct answer entered on a second try, he completely dismissed my request for help because he saw that I found the correct answer. UGH. This time I specifically stated how I got the answer and that I do not object to him deducting credit for it, but I really need help with the solution. Let see how it goes.

UGH. Stupid stupid stupid.

 

[rhino]

So, after I did as much as I could on the surface area problem set, I decided to get started on the "physical applications" section. I am pleased to announce that I whipped through those pretty quickly. I had four left to do today, two of which are completed. It's a wee bit advantage when working applications problems to be, oh, I dunno, a mechanical engineer and physics instructor. In addition, it reminded why engineering students have to complete three calculus courses and start the first of two differential equations courses before they can start studying engineering mechanics (statics & dynamics).

The physics I taught at Ivy Tech was non-Calculus-based "college physics." That experience and seeing how simplified so many of the concepts were (especially electricity and magnetism) was a huge clue that my math foundation had crumbled and needed repairs.

Still don't know where I'm going with all of this, but data analysis & modeling still looks promising.

Another thing that struck me is this: when I'm having trouble with my homework, where the heck are all of those super geniuses who would drop into the "global warming" topics to educate us poor savages and grace us with their superior intellects? I could use some help!

 

[actaeon277]

So, after I did as much as I could on the surface area problem set, I decided to get started on the "physical applications" section. I am pleased to announce that I whipped through those pretty quickly. I had four left to do today, two of which are completed. It's a wee bit advantage when working applications problems to be, oh, I dunno, a mechanical engineer and physics instructor. In addition, it reminded why engineering students have to complete three calculus courses and start the first of two differential equations courses before they can start studying engineering mechanics (statics & dynamics).

The physics I taught at Ivy Tech was non-Calculus-based "college physics." That experience and seeing how simplified so many of the concepts were (especially electricity and magnetism) was a huge clue that my math foundation had crumbled and needed repairs.

Still don't know where I'm going with all of this, but data analysis & modeling still looks promising.

Another thing that struck me is this: when I'm having trouble with my homework, where the heck are all of those super geniuses who would drop into the "global warming" topics to educate us poor savages and grace us with their superior intellects? I could use some help!

We're not trained to handle this
https://www.youtube.com/watch?v=ldMKkfPSB7E
[video=youtube;ldMKkfPSB7E]https://www.youtube.com/watch?v=ldMKkfPSB7E[/video]

 

[actaeon277]

Maybe go to that thread, and ask?

 

[littletommy]

Was a post deleted, or do I need to put the beer away for the day?
(Hopefully a post was deleted, I’m only on my second beer)

 

[rhino]

Was a post deleted, or do I need to put the beer away for the day?
(Hopefully a post was deleted, I’m only on my second beer)

Looks like maybe something was in between Actaeon last two messages? If so, I missed it too.

Assignments due tonight are in the can. I "cheated" on a couple of the problems that specified answers rounded to specific decimal places instead of exact answers by integrating them numerically.

 

[actaeon277]

No. You talked about super geniuses in the global warming thread.
So I asked, why not go to that thread, the global warming thread, and ask those super geniuses.

 

[rhino]

No. You talked about super geniuses in the global warming thread.
So I asked, why not go to that thread, the global warming thread, and ask those super geniuses.

Ahh! Thank you for the clarification, sir!

Unfortunate, those who self-identified are either on my IGNORE list or banned or both. D'OH!

 

[actaeon277]

Ahh! Thank you for the clarification, sir!

Unfortunate, those who self-identified are either on my IGNORE list or banned or both. D'OH!

Not going to "un-ignore" them long enough for them to demonstrate their superior knowledge?

 

[riverman67]

Just for the record
Calculus is THE reason I'm not an engineer.
I would rather clean out a septic tank on Saturday night than think about doing calculus equations again

 

[rhino]

Not going to "un-ignore" them long enough for them to demonstrate their superior knowledge?

Haha! Probably not.

 

[rhino]

Not going to "un-ignore" them long enough for them to demonstrate their superior knowledge?

Haha! Probably not.

Just for the record
Calculus is THE reason I'm not an engineer.
I would rather clean out a septic tank on Saturday night than think about doing calculus equations again

Calculus is the starting point!

 

[red_zr24x4]

Playing WoW. 50 yr old man playing video games... only thing worse is my 52 yr old wife playing it too

 

[rhino]

Playing WoW. 50 yr old man playing video games... only thing worse is my 52 yr old wife playing it too

If you're doing it together and you're enjoying it: NOT LAME!

Lame would be if one of you ignored the other while playing a game.

 

[femurphy77]

Changed the starter on the GF's Civic. (Not actually lame since the dealer quoted her $800 and I did it for the price of the starter, payment due later)

 

[actaeon277]

Changed the starter on the GF's Civic. (Not actually lame since the dealer quoted her $800 and I did it for the price of the starter, payment due later)

Any promises, made more than 10 feet from the bed, or 10 minutes from the event, are often null and void when coupon is presented for redemption.