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Units

Posted: Thu Oct 18, 2018 11:38 pm
by Henry Krasner 1C
What unit does J.s^(-1) translate into, and how would we use this new unit to calculate the correct unit for finding wavelength, in say, the equation of λ=h (unit of J.s^(-1)/mv?

Re: Units

Posted: Thu Oct 18, 2018 11:40 pm
by Summer de Vera 2C
It translates into kgm^2/s because a joule is kgm^2/s^2, and if you divide it by 1/s, it gets to this unit.

Re: Units

Posted: Sun Oct 21, 2018 1:32 pm
by 804994652
1 joule = 1kg·m^2·s^-2
If you divide it by s-1. One of the 's' cancels out and you get 1kg·m^2·s^-1.

Re: Units

Posted: Sun Oct 21, 2018 9:14 pm
by Jchellis 1I
Its important to remember that we use kg instead of grams for SI units. I know I always forget!

Re: Units

Posted: Mon Oct 22, 2018 12:19 am
by Tatum Keichline 2B
Joule is kgm^2/s^2, but multiplying my 1/s cancels one of the s units, making kgm^2/s

Re: Units

Posted: Mon Oct 22, 2018 2:55 am
by Mhun-Jeong Isaac Lee 1B
Just another reminder too is that Herz = s^-1. I find it helpful to convert Hz to s^-1 so that if units are being multiplied or divided, it's easier to see how things cancel out.

Re: Units

Posted: Thu Oct 25, 2018 10:13 am
by Daniel Chang 3I
a Joule multiplied by 1/s is composed of 1kgm^2/s in its simplest form

Re: Units

Posted: Thu Oct 25, 2018 7:36 pm
by 105002507
When do we use kg?

Re: Units

Posted: Thu Oct 25, 2018 8:07 pm
by Amy Dinh 1A
105002507 wrote:When do we use kg?


We use kg when we are calculating energy, since the units are in jules (kg·m^2·s^-2)

Re: Units

Posted: Thu Oct 25, 2018 11:14 pm
by lukezhang2C
It should follow e=mc^2 for photons, which is kgm^2/s^2

Re: Units

Posted: Sun Nov 04, 2018 11:28 pm
by duverge_maciel
If a calculation is in Hz, does that mean it will always be a positive value?

Re: Units

Posted: Fri Oct 11, 2019 9:26 am
by Kelvin Chung 1C
Do we need to know the SI unit equivalents for each term, like the joule?

Re: Units

Posted: Fri Oct 11, 2019 7:03 pm
by AniP_3B
Kelvin Chung 1C wrote:Do we need to know the SI unit equivalents for each term, like the joule?


I am not sure if you need to know them, but for the quantum section it would extremely helpful to know that a J is equal to kg*m^2*s^-2

Re: Units

Posted: Fri Oct 11, 2019 8:08 pm
by Mellanie Gamero 4D
I'm sure that it is important that you know the proper SI units for each term because there will be many problems which can be solved by canceling out, thus helping you find a corresponding answer for that problem in the simplest form.

Re: Units

Posted: Sun Oct 13, 2019 3:23 pm
by Drew Myers 3A
Will there ever be a time where we need to use megagrams or gigagrams or will we likely only go as big as kilograms?

Re: Units

Posted: Sun Oct 13, 2019 4:46 pm
by Veronica Lu 3L
I think for the most part it would only go as far as kilograms, but in any case, if megagrams and gigagrams were necessary I think we would be provided a formula sheet to convert the numbers.

Re: Units

Posted: Sun Oct 13, 2019 5:00 pm
by GEOVANNAO_3F
If you ever forget unit conversions just remember:

K- King
H- Henry
D- Died
U- Unusually
D- Drinking
C- Chocolate
M- Milk

Re: Units

Posted: Wed Oct 16, 2019 3:35 pm
by PriscillaLi_3G
Is it necessary that we put in the units while showing our work?