Jump to content

Relativity mix-up............

Featured Replies

Do Joules divided by Kilograms per Square Meter equal Miles per Hour?

ie does E=mc^2?

Not quite. The correct expression would be: Joules divided by Kilograms are equivalent to metres-squared per second-squared.

  • Author
Not quite. The correct expression would be: Joules divided by Kilograms are equivalent to metres-squared per second-squared.

 

Newton meters/wg=square of light speed?

I feel that the units are inconsistent.could you break it down for me,please?

1 joule is, among other things,

  • The work done on some object by a force of one newton as the object moves a distance of one meter, from [math]W=\oint \mathbf F \cdot d\mathbf l[/math]
  • The kinetic energy of a 2 kilogram mass moving at the non-relativistic velocity of 1 meter per second, from [math]KE=\frac 1 2 m v^2[/math]

 

These expressions have the same fundamental units and the same numerical value:

 

[math]1\,\text{joule} = 1\,\text{newton}\,*\,1\,\text{meter} = 1\,\text{kg}\,\text{meter}/\text{second}^2\,*\,1\,\text{meter} = \frac 1 2\,*\,2\,\text{kg}\,*\,(1\,\text{meter}/\text{second})^2[/math]

 

Energy has units of mass*velocity squared. The expression [math]mc^2[/math] has units mass*velocity squared -- energy.

Archived

This topic is now archived and is closed to further replies.

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.