Units for a Joule  [ENDORSED]

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Esther Ahn 4I
Posts: 30
Joined: Fri Sep 28, 2018 12:29 am

Units for a Joule

Postby Esther Ahn 4I » Sat Oct 13, 2018 10:50 pm

Can someone please explain why the units for a Joule are 1 kg*m^2/s^2 :) I’m just a bit confused as to where this is coming from.

Jeannine 1I
Posts: 73
Joined: Fri Sep 28, 2018 12:27 am

Re: Units for a Joule

Postby Jeannine 1I » Sat Oct 13, 2018 11:25 pm

A "Joule" is a unit of energy, and is named after the man who discovered it. I think we just use the term "joule" as a shorter way to say 1 kg*m^2/s^2, and it lets people know automatically that we're referring to energy. I hope that helps at least a bit haha(: !

Jacqueline Duong 1H
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

Re: Units for a Joule  [ENDORSED]

Postby Jacqueline Duong 1H » Sat Oct 13, 2018 11:49 pm

This is because joule is a unit of work, and the equation for work is: work = force x displacement. When you expand this, you get work = mass x acceleration x displacement. The units for mass is kg, for acceleration is m/s^2, and for displacement is m. As a result, when you times them all together, you get kg(m^2)(s^-2). I hope this helps!

Posts: 56
Joined: Fri Sep 28, 2018 12:25 am

Re: Units for a Joule

Postby monikac4k » Sun Oct 14, 2018 3:41 pm

I know other people already gave good explanations for the units of a joule, but I wanted to share a way to sort of remember the units. When I took AP Physics in high school, my teacher told us a little phrase to remember the units: "Newton, meter (meet her). She's a Joule (jewel)!" From physics we learned that a joule, in terms of units, is equal to a newton times a meter. Of course then you need to know the units of a Newton, a unit used to measure force, which is kg*m*s^-2. It is a funny way to remember units.

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