(July 23, 2019 at 12:44 pm)comet Wrote:(July 23, 2019 at 10:10 am)polymath257 Wrote: The energy in the energy-momentum 4-vector is the kinetic energy. The other three components of the 4-vector are the usual three components of the momentum.
Potential energy is, ultimately, the kinetic energy of the force carrying particles. So *all* energy is ultimately kinetic energy.
You also mentioned "energy is the Time component of ..." , whats that mean? energy is the time component?
A vector has components. So, for example, a vector in two dimensions has an x-component and a y-component. A vector in three dimensions has three components: x,y, and z. A vector in four dimensions has four components: x,y,z, and t.
So, in the energy-momentum 4-vector, the x,y, and z components are the amounts of momentum in the x,y, and z directions. The t component is the energy.
Now, truthfully, if you didn't know what a vector is, you don't have even enough *classical* physics to have a *basic* knowledge of physics, and thereby even a basic understanding of energy. And to have a *modern* view requires a LOT more than just some knowledge of vector calculus.
