If speed is relative, then energy should be relative as well.
Relativity
Say you are in space with one of your friends.
And what you see is the distance between you and your friend is decreasing.
But which is true?
A) You are moving towards your friend.
B) Your friend is moving toward you.
C) Both of you are moving toward each other.
Here's another scenario
say 3 friends are demonstrating relativity, Adam, Bob, and Celia.
Adam is driving 10 m/s on the road.
Bob is driving 8 m/s on the same road as Adam.
Celia is Observing Adam and Bob beside the road.
This is what they should see.
Adam is leaving Celia with a speed of 10 m/s and leaving Bob with a speed of 2 m/s.
Bob is lacking behind Adam with a speed of 2 m/s and leaving Celia with a speed of 8m/s
When we are dealing with directions or locations, we need a reference point. If the distance between an object and the reference point is changing, then we know that the object is moving.
In the scenario, the reference could be a rock on the ground or the Earth.
Energy
Energy is the ability to do work (Product of Force and Displacement).
We know that the Kinetic Energy of an object is 0.5 x Mass x Velocity^2.
Velocity is a vector, so it needs a reference point, it could be the earth or the sun.
Say you are sitting in your room.
Relative to the earth, you are not moving, therefore your velocity is 0m/s, meaning you have no Energy relative to the Earth.
Relative to the sun, you are moving as the Earth is orbiting and rotating around the sun, therefore you have a certain velocity, meaning you have Energy relative to the Sun.
So next time when you think that you have no energy... ; )
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