Thread: What is the essence of force ?

1. What is Force ?
From F=ma We knew that Force is something making other things changed their movement .
But is it really what Newtron thought ?

I don't think so .
I guess when Newtron was studying the movement of object ,
he was wondering :
"Why things can move ?"
"Why we push things which will move ?"
"What is the law ?"

We know nothing about the essence of force if we consider it deeply .
When speed is being changed , that needs some condition .
But what the heck condition is it ?
We knew it will follow some laws .
We found m~1/a ; the more mass , the harder we move it
When we study deeply, We found dp/dt=F
Think of small-sized , F=kqq'/d^2 ,
or in big-sized , F=Gmm'/d^2

"How could things be moved?"
"Because of Force ;"
"What is Force ?"
"F=ma"

"Shoot.."

In short , I define Force "nothing" ;
it doesn't exist really as time .
It is a nature or law of our world .
One way to describe our world .

Please tell me , if my way is wrong .
Thank you

2.

4. Originally Posted by drakmage
What is Force ?
an interaction which causes mass to accelerate.
pushes and pulls?

yea that leads one to F=ma, but thats how force is defined for motion with constant mass.

5. yea that leads one to F=ma, but thats how force is defined for motion with constant mass.
this defintion only works when v<<c else the defintion goes for newtons original defintion wich where F=dp/dt

its the same definitons einstein used

6. I think mass isn't fundamental actually, but energy is. Try to think of force without any mass. You can still think in terms of momentum because a "massless" photon has momentum, and the momentum hf/c is the energy hf divided by c, which is distance over time. Energy is stress multiplied by volume, and stress is force per unit area. This means force is energy divided by distance. You have to think of energy as the amount of tightness in a cube, and the force is what you see when you look at it from some particular angle.

7. I think mass isn't fundamental actually, but energy is.
they are the same thing
E=MCÂ˛
and no mike dont butt in here

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