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Kenny022593
09-10-2009, 07:56 PM
Alright so my teacher today did not teach us how to do the homework he gave us a useless problem to do the entire class. so, one of the questions is How many ohms are there in a 7.85-megohm resistor? i look in the unit conversion factors table in the book but i see no ohms or hm any help? lol

*Edit* i think i got it thanks to the new invention of texting a friend. So... 1 mego hm is equal to 1million ohm so the answer is 7.85 x 10^3 ohm.

Thanks =P

jonnythan
09-10-2009, 08:07 PM
Basic SI prefixes.

"Mega-" means 10^6, or 1 million. A megabyte is a million bytes (well, that's a complicated issue, but still). A megaton is a million tons. A megameter is a million meters.

7.85 * 10^3 = 7.85 * 10 * 10 * 10 = 7850. That's 7.85 kiloohms. 7.85 megaohms is 7.85 * 10^6 ohms, or 7,850,000 ohms.

Kenny022593
09-10-2009, 08:09 PM
Thanks =D

There are no answers in the back of the book so i cant check when i know i am wrong lol so i have to go with my gut! Yes to second day of physics

TENNIS_IS_FUN
09-11-2009, 02:54 AM
If you have an incompetent teacher for physics I would advise you to drop that class immediately!! What you described in your OP pretty much described exactly the style of teaching my teacher used! He was useless...he would give us problems, give us a couple minutes to solve them, then have an overhead projection of the answers and not explain anything. Physics will only get harder...much much harder....I was a day or two late for dropping classes so i had to stick with it for one whole year. I learned absolutely nothing at all and opted not to take the AP test. I ended up getting a C grade both semesters but he gave it to be because nobody in the class knew what they were doing.

skyzoo
09-11-2009, 03:21 AM
I had AP Phys yesterday and I'm semi scared for my GPA

GPB
09-11-2009, 04:16 AM

HellBunni
09-11-2009, 11:57 AM
have you taken any other science classes?

you should learn your perfixes (fixed =)), as they are pretty basic. And applies across all sciences and math that use measurements.

there is always google, they perform unit conversions for you.

jonnythan
09-11-2009, 11:57 AM
Prefixes, not suffixes ;)

aphex
09-11-2009, 01:06 PM
Alright so my teacher today did not teach us how to do the homework he gave us a useless problem to do the entire class. so, one of the questions is How many ohms are there in a 7.85-megohm resistor? i look in the unit conversion factors table in the book but i see no ohms or hm any help? lol

*Edit* i think i got it thanks to the new invention of texting a friend. So... 1 mego hm is equal to 1million ohm so the answer is 7.85 x 10^3 ohm.

Thanks =P

in terms you'll understand:

how many big macs are there in a MEGA-mac?

http://4.bp.blogspot.com/_3-h3lqEIcx0/Raf11nK0PTI/AAAAAAAAAO8/0TQyTN81OEc/s400/Mega+mac.jpg

ollinger
09-11-2009, 01:12 PM
I agree Kenny should drop physics. If it doesn't occur to you to look up the prefix "mega" to try to solve the problem, you might not belong in a physics class.

meowmix
09-11-2009, 02:57 PM
Alright so my teacher today did not teach us how to do the homework he gave us a useless problem to do the entire class. so, one of the questions is How many ohms are there in a 7.85-megohm resistor? i look in the unit conversion factors table in the book but i see no ohms or hm any help? lol

*Edit* i think i got it thanks to the new invention of texting a friend. So... 1 mego hm is equal to 1million ohm so the answer is 7.85 x 10^3 ohm.

Thanks =P

Um... That's incorrect, btw. You said yourself that 1 megaohm is 1 millions ohms... That's 1*10^6 ohms... multiplied by 7.85, and you've got 7.85*10^6 ohms.

And really... if you're in AP Physics, you should know that. Even if you didn't, it would have been more worth your time to simply google that one.

As for a bad teacher, well, how's he a bad teacher? We get a lot of homework that the teacher hasn't been able to teach yet, and it's up to us to figure it out. It was the same thing in my AP Chem class. You have to realize that he's got 8 months to teacher you a lot of material. Figure it out by yourself, or get in groups with friends and have physics parties.

dave333
09-11-2009, 03:20 PM
Go spend 20-30 bucks on a good AP Physics review book (I used Princeton Review). Worth every penny.

SuperJimmy
09-11-2009, 03:29 PM
Not to be mean or anything, but when it asks you about how many OHMs are in 7.85 megOHM, your first thought was to think 'hm' was the unit of measurement? Hopefully it was just a very big brain fart.

Also, as an FYI, an 'ohm', commonly depicited by the capital omega symbol, is the measure of electrical resistance or impedance between two points. You will generally see this in circuit analysis. I dont believe AP Physics goes much into that, if at all.

skyzoo
09-11-2009, 03:41 PM
in terms you'll understand:

how many big macs are there in a MEGA-mac?

http://4.bp.blogspot.com/_3-h3lqEIcx0/Raf11nK0PTI/AAAAAAAAAO8/0TQyTN81OEc/s400/Mega+mac.jpg
Theres a mega mac? whhhaaatatatatatatataat!!!!!!!!!!!

r2473
09-11-2009, 03:43 PM
Theres a mega mac? whhhaaatatatatatatataat!!!!!!!!!!!

The Chinese are beating us at EVERYTHING!!!

skyzoo
09-11-2009, 03:47 PM
The Chinese are beating us at EVERYTHING!!!
Four patties and twice the special sauce! forget physics I need to get to the bottom of this.

skyzoo
09-11-2009, 03:48 PM

skyzoo
09-11-2009, 03:50 PM

I'm feeling a class trip to Japan

09-11-2009, 04:26 PM
Type "7.85 megaohm to ohm" in google. It works for any conversion you want to make.

diredesire
09-11-2009, 04:31 PM
Type "7.85 megaohm to ohm" in google. It works for any conversion you want to make.

This man knows how to use google. Listen to this man.

You should learn your scientific/conversion units if you plan to do ANYTHING science related. Even if you don't, it's likely you will be required to take a science class. Knowing how to convert a picoliter to a Liter should be useful for a variety of sciences.

This isn't just a 'stupid' question that has no practical application, unit conversion (this isn't really even unit conversion) is something you're going to see very, very often. Just know the pre-fixes, and you should be good to go.

Also, watch back to the future, and then make sure you know the difference between a jigawatt, and a gigawatt.
:)