Help Keep Boards Alive. Support us by going ad free today. See here: https://subscriptions.boards.ie/.

https://www.boards.ie/group/1878-subscribers-forum

Private Group for paid up members of Boards.ie. Join the club.

Hi all, please see this major site announcement: https://www.boards.ie/discussion/2058427594/boards-ie-2026

1kg of mass = 9 x 10^16 joules of energy

26-05-2011 10:25PM

#1

digme

Closed Accounts Posts: 4,584 ✭✭✭

Join Date: December 2009

Posts: 4174

wtf?

0

Comments

#2 26-05-2011 10:34PM

stealinhorses

Registered Users, Registered Users 2 Posts: 774 ✭✭✭

Join Date: October 2010

Posts: 770

E = mc^2
E = (1)(3x10^8)^2
E = (1)(9x10^16)
E = 9x10^16 J

0
#3 26-05-2011 10:39PM
digme

Closed Accounts Posts: 4,584 ✭✭✭

Join Date: December 2009

Posts: 4174
E = mc2 into its components and write out the terms fully we get:
E = energy (measured in joules)

m = mass (measured in kilograms)

c = the speed of light (186,000 miles per second, or 3 ´ 108 ms-1)

The equations are fine but it's mind boggling.
How can there be so much energy from 1kg of something?
And why can't we use it? And what has light got to do with it?

0
#4 26-05-2011 10:57PM

Podge_irl

Moderators, Sports Moderators, Paid Member Posts: 33,049 Mod ✭✭✭✭

Join Date: October 2007

Posts: 33012

digme wrote: »

And why can't we use it? And what has light got to do with it?

Because you'd need a kg of antimatter to actually get all that energy out of it.

Using E=mc^2 on lumps of mass isn't really the most instructive thing in the world.

0
#5 26-05-2011 11:00PM

digme

Closed Accounts Posts: 4,584 ✭✭✭

Join Date: December 2009

Posts: 4174

So kind of like potential energy in electronics?

0