Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Notifications
Mark all as read
Q&A
Post

Is $E=mc^2$ true for all frame of references?

+1
−1

Which one is correct? $$E=mc^2$$ or $$E^2=(mc^2)^2+(pc)^2$$

I mostly seen $$E=mc^2$$ from my childhood, and when I was learning problem solving in relativistic mechanics I had seen $$E^2=(mc^2)^2+(pc)^2$$ I know than if a frame at rest then momentum is $0$ hence $$E=mc^2$$ is true. But if a frame is not at rest then $E =mc^2$ true for that frame?

Why does this post require moderator attention?
You might want to add some details to your flag.
Why should this post be closed?

2 comment threads

Define your terms. (2 comments)
Rest energy and momentum (1 comment)

Comments on Is $E=mc^2$ true for all frame of references?

Rest energy and momentum
gmcgath‭ wrote 10 months ago:

I'm very rusty on this topic, so I'm offering a comment rather than an answer. Feel free to correct anything that looks dumb here.

In special relativity, there is no such thing as a "rest" frame of reference. All non-accelerated frames of reference have equal standing. But the classic Einstein equation refers to rest energy, i.e., the potential energy that can be obtained by converting mass. The more general form of the equation includes the energy of momentum (in a given frame of reference) as well, so it includes kinetic as well as potential energy. Kinetic energy obviously does depend on the reference frame. Both equations are correct; it depends on what you're trying to do. This page may be helpful: http://www.phys.ufl.edu/~acosta/phy2061/lectures/Relativity4.pdf

This community is part of the Codidact network. We have other communities too — take a look!

You can also join us in chat!

Want to advertise this community? Use our templates!

Like what we're doing? Support us! Donate