Re: A high school question about Newton's third law for bodies in motion


"java" <javadesigner@xxxxxxxxx> wrote in message
news:fpldp9$54j3$1@xxxxxxxxxxxxxxxxxxxx
| Does Newton's third law apply to bodies in motion ? (not in
| a state of equilibrium).
|

Yes.

| SPEIFICALLY:
|
| A 1 ton box falling in a column of almost empty air,
| containing only a few air molecules ?
|
| The box will fall under gravity and exert a force
| (equal to it's weight) on the air molecule.
|
| The air molecule will exert the SAME force back on
| the box.
|
| By newton's third law.

Yes.

|
| Therefore the box should not move at all.

Nonsense.

|
| UNLESS the air molecule moves.

Ok, so it moves.


| But then the system is not in equilibrium and newtons' third
| law cannot really be held to apply, correct ?

Wrong.
"To every action there is always opposed an equal reaction; or the mutual
actions of two bodies upon each other are always equal, and directed to
contrary parts."

Where did Newton say anything about equilibrium?









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