Newton's First Law: At Rest or In Motion?

[lightbender]

For Newton's first law, which one is correct?

1. All objects that are at rest, stay at rest; all objects that are in motion stay in motion, unless acted upon an unbalanced force.

Or

2. All objects that are at rest, stay at rest; all objects that are in motion stay in motion, unless acted upon an outside force.

Thank you!

 

[phinds]

What do you think and why? It is not the purpose of this forum to spoon-feed answers. You need to make some effort yourself.

 

[lightbender]

This is not a homework question!
I am just confused because some websites say number 1 while others say number 2

 

[dipole]

explain the difference between the two statements. What does an "outside force" mean, and what would an "unbalanced force" be?

 

[lightbender]

I do not know!

 

[sophiecentaur]

I do not know!

It is only 'words' that you appear to have a problem with.
Start from the standpoint that Newton One is probably right (go to a third source, perhaps) and see which of those two alternatives could be 'wrong' or just a strange way of putting it, in your view. Try to reconcile them together rather than looking for a wrong one.

 

[bobie]

For Newton's first law, which one is correct?

1. All objects that are at rest, stay at rest; all objects that are in motion stay in motion, unless acted upon an unbalanced force.
2. All objects that are at rest, stay at rest; all objects that are in motion stay in motion, unless acted upon an outside force.

The two sentences are identical but for an adjective, unbalanced is not appropriate, according to Newtons original formulation outside/ external is more appropriate:

Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.
Law I: Every body persists in its state of being at rest or of moving uniformly in a straight line unless it is compelled to change its state by forces impressed.