# Physics class - I'm slightly worried **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [August 27, 2002, 10:58pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838 "2002-08-27T22:58:12Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![zweisamkeit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zweisamkeit/32/4360_2.png) [@zweisamkeit](https://boards.straightdope.com/u/zweisamkeit)\ **Post date:** [August 27, 2002, 10:58pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/1 "2002-08-27T22:58:12Z")
Dang, I’d be worried too! ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [August 27, 2002, 11:09pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/2 "2002-08-27T23:09:50Z")
Don’t worry, the hamster that’s both dead and alive at the same time doesn’t come until the end of the second semester. ---
**Author:** ![Sir\_Dirx](https://avatars.discourse-cdn.com/v4/letter/s/b77776/32.png) [@Sir\_Dirx](https://boards.straightdope.com/u/Sir_Dirx)\ **Post date:** [August 27, 2002, 11:16pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/3 "2002-08-27T23:16:01Z")
Wait a minute, I don’t see my post on here. Is this just on my computer, or did it get eaten? ---
**Author:** ![Bedhead](https://avatars.discourse-cdn.com/v4/letter/b/f07891/32.png) [@Bedhead](https://boards.straightdope.com/u/Bedhead)\ **Post date:** [August 27, 2002, 11:26pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/4 "2002-08-27T23:26:19Z")
someone definitely ate it. sorry man. ---
**Author:** ![Sir\_Dirx](https://avatars.discourse-cdn.com/v4/letter/s/b77776/32.png) [@Sir\_Dirx](https://boards.straightdope.com/u/Sir_Dirx)\ **Post date:** [August 27, 2002, 11:42pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/5 "2002-08-27T23:42:33Z")
Argh. I had a nice big post about it all, and I thought I got it out before my computer froze, but I guess I’m just not that lucky. Alright, well, the short short version then… My physics prof (I’m a junior on college, keep in mind) absolutely detests calculators (his exact words). That’s not the problem, because he still lets us use them. But the problem is, he’s decided that inside his classroom, the acceleration due to gravity is not 9.8m/s[sup]2[/sup], but 10. Just plain old 10m/s[sup]2[/sup]. I’m sitting here musing about how I don’t much like the idea of tweaking natural laws just because it’s easier to multiply and divide by 10 than it is by 9.8, but then he makes another statement. For his class, pi = 3. Not 3.14, not even 3.1, just 3. Maybe it’s just me, but I think this is just a _little_ bit wrong. I may be horrible at math, but if I’m going to learn physics then I better damn well learn it the right way. Am I right in being concerned over this, or should I just shut up and be thankful for his simplified equations? Dirx (and no, I can’t change sections, 'cause his is the only one that fits my already precarious schedule) ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [August 27, 2002, 11:54pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/6 "2002-08-27T23:54:27Z")
Eh. I don’t think it’s that big a deal. You’re learning to apply the equations, which is what’s important in physics. You can go back and plug in the right numbers later. ---
**Author:** ![Gopher](https://avatars.discourse-cdn.com/v4/letter/g/a183cd/32.png) [@Gopher](https://boards.straightdope.com/u/Gopher)\ **Post date:** [August 27, 2002, 11:55pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/7 "2002-08-27T23:55:54Z")
Well in the equations while you’re doing the work, write in G or whatever letter for the acceleration, and the weird sign for pi…you’ll learn the stuff right. Just gotta keep on reminding yourself the correct values before you forget. It’s not like anything is really different. ---
**Author:** ![Sir\_Dirx](https://avatars.discourse-cdn.com/v4/letter/s/b77776/32.png) [@Sir\_Dirx](https://boards.straightdope.com/u/Sir_Dirx)\ **Post date:** [August 28, 2002, 12:37am UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/8 "2002-08-28T00:37:53Z")
Idunno. “Pi = 3” still gives me the crawlies. I mean, look at it this way: What if your english teacher said “I absolutely detest dictionaries. In my class, _hors d’oeuvre_ will be spelled _orderve_, because that’s simpler.” It’s just fundamentally wrong to me. ---
**Author:** ![Giraffe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giraffe/32/129_2.png) [@Giraffe](https://boards.straightdope.com/u/Giraffe)\ **Post date:** [August 28, 2002, 12:46am UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/9 "2002-08-28T00:46:21Z")
**Sir Dirx** , your professor is doing you a favor. What you are doing is getting a feel for the order of magnitude of the answer, by taking reasonable estimates of the constants. When faced with an answer like 15g/4\*pi[sup]2[/sup], you’d normally just break out the calculator and write down whatever number it gave you. Now, you’ll only get the answer to within 10%, but you can do it in your head, so you can keep track of how significant it is as you do the calculation. Are you finding a distance of a meter? A million kilometers? A micron? Calculators in some ways turn physics students into little plug and chug robots, who can only solve a problem if you give them the equation and the values of all but one of the variables. ---
**Author:** ![Sir\_Dirx](https://avatars.discourse-cdn.com/v4/letter/s/b77776/32.png) [@Sir\_Dirx](https://boards.straightdope.com/u/Sir_Dirx)\ **Post date:** [August 28, 2002, 1:00am UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/10 "2002-08-28T01:00:10Z")
Yeah, I do understand your point, **Giraffe** , and I really do appreciate what he’s trying to do for us. I’m not gonna be real fussy about it and complain to him or anything, but it’s still a bit weird to be using those values. Oh well, whatever makes this course easier I guess… ---
**Author:** ![Giraffe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giraffe/32/129_2.png) [@Giraffe](https://boards.straightdope.com/u/Giraffe)\ **Post date:** [August 28, 2002, 3:52pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/11 "2002-08-28T15:52:55Z")
Don’t get me wrong – it _is_ freaky to write down pi as just 3. But it’s for a reason, at least. By the way, what are you studying, **Sir Dirx**? If you’re in pre-med, then you’re going to be really really glad he’s doing this. The MCAT doesn’t allow calculators but does require numerical calculation. i’ve taught some MCAT prep courses, in which I had to convince some premeds who already thought physics was the stupidest thing ever that it made sense to write pi as 3 and 9.2 as 10, in order to quickly get an answer. They were not impressed. ---
**Author:** ![Sir\_Dirx](https://avatars.discourse-cdn.com/v4/letter/s/b77776/32.png) [@Sir\_Dirx](https://boards.straightdope.com/u/Sir_Dirx)\ **Post date:** [August 28, 2002, 4:04pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/12 "2002-08-28T16:04:15Z")
I’m not pre-med, luckily. I’m a straight Bio major at the moment, but I’m doing undergraduate research in paleontology and hope to go on to grad school to get a paleo degree. I’ve already heard horror stories about the MCATs; that’s definitely not something I want to do… ---
**Author:** ![g8rguy](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@g8rguy](https://boards.straightdope.com/u/g8rguy)\ **Post date:** [August 28, 2002, 6:20pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/13 "2002-08-28T18:20:08Z")
Hmm… I’ve never stuck with just using pi=3, meself. Sometimes pi=3, sometimes pi=sqrt(10). It all depends on which cancels things out more neatly. ---
**Author:** ![Mtgman](https://avatars.discourse-cdn.com/v4/letter/m/b5a626/32.png) [@Mtgman](https://boards.straightdope.com/u/Mtgman)\ **Post date:** [August 28, 2002, 10:34pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/14 "2002-08-28T22:34:24Z")
What about pi=22/7 ? That comes in handy for cancellation sometimes. Steven ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [August 28, 2002, 10:53pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/15 "2002-08-28T22:53:34Z")
I had a prof who called calculators “punch machines.” We had to learn Trig equations in terms of Pi. And I had a physics prof who used the 10 instead of 9.8…fortunately, Pi was still Pi. But in the age of computers, so many cheapo calculators have the snazzy equations BUILT IN. You ain’t learnin’ NUFFIN if all you do is RCL 3, and plug in the values when you’re prompted. Your instructor wants to see your WORK, not how well you can remember your times tables. I remember being told a zillion years ago, if you just write down the ANSWER, even if it is correct, you’re gonna get the problem WRONG. And if you work it out correctly, but multiply 3 x 2 and get 5, chances are, you’ll get the credit for the problem. Bottom line: it’s HIS class, he can run it however he likes. Just chalk it up to learning how to be versatile. ~VOW ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [August 28, 2002, 11:04pm UTC](https://boards.straightdope.com/t/physics-class-im-slightly-worried/125838/16 "2002-08-28T23:04:44Z")
I had a prof who called calculators “punch machines.” We had to learn Trig equations in terms of Pi. And I had a physics prof who used the 10 instead of 9.8…fortunately, Pi was still Pi. But in the age of computers, so many cheapo calculators have the snazzy equations BUILT IN. You ain’t learnin’ NUFFIN if all you do is RCL 3, and plug in the values when you’re prompted. Your instructor wants to see your WORK, not how well you can remember your times tables. I remember being told a zillion years ago, if you just write down the ANSWER, even if it is correct, you’re gonna get the problem WRONG. And if you work it out correctly, but multiply 3 x 2 and get 5, chances are, you’ll get the credit for the problem. Bottom line: it’s HIS class, he can run it however he likes. Just chalk it up to learning how to be versatile. ~VOW