Kinetic Energy Change in Particle: Earth vs Space Observation

[HungryChemist]

Alright, I was wondering if Change in Kinetic energy of a particle (after undergoing a constant force acting on it) would be oberserved to be the different value measured from two different inertial reference frames.

Here's one particular case...Say you're on Earth and I on a space ship. We are both observing the same particle in the space and there's a force action on the particlee. The particle displace it self through surface, therefore there's work done on the particle due to the force and therefore it will change it's kinetic energy. But, would that change in kinetic energy of the particle agree if you were to do the same calculation from the spaceship?

 

[Meir Achuz]

Energy is one component of a four-vector.
So energy and change in energy will be different in different Lorentz systems.

 

[Crosson]

The answer is yes, the calculation would be different. Additionally, no one ever said that energy is conserved when changing reference frames.