Can anyone describe for me in laymans terms,the understanding of the "equivalence principle" in a paragraph?

Question

This must be in General Realitivity and not Special Realitivity. Thank You

Answer 1

Great question!

The equivalence principle states that being at rest in a gravitational field is equivalent to accelerated motion. One easy way to understand this is to understand the equivalence between 'free fall' and 'zero gravity.' Of course, there is no such thing as zero gravity - gravitational fields are infinite. But an object in free fall moves like (or you feel like, if you are the one in free fall) there is no gravity. That's because of the equivalence principle. When you are in normal accelerated motion, objects act differently - you are pressed against the seat, or two objects are pressed together, or water is pressed against the edges of a spinning bucket. But when you are moving freely under the influence of a gravitational field (i.e., in 'free fall,') there is no such pressure. It's when you stop - sit in the chair, or put the two balls two object together on the ground - at rest in the gravitational field - that there is a pressure, just like the pressure of acceleration. This not only works in this thought experiment, but also in the mathematics of gravity and acceleration.

I tried to do it in one paragraph - hope that helped. There's more at the link below.

Answer 2

Hi. In theory it means that if you are, say, riding in an elevator with an upwards acceleration you can't distinguish this acceleration from gravity. I believe this to be false because gravity has a center line. Two objects dropped in the elevator will move towards the center of the gravity field, whereas if they are dropped in an accelerating elevator they follow parallel paths. Make sense?