Hey Neo!

[Revival]

What was Newton's second law?

[Neo]

F=ma

[Revival]

Ok, thanks.

Force is in Newtons
Acceleration is m/s2

But what's mass usually measured in?

[Xantar]

Is this for homework or something? :hmm:

Might as well post all three just in case.

1. An object remains at rest or in motion unless acted upon by an external force. (The concept of inertia).

2. In the presence of a net force, an object experiences acceleration directly proportional to the net force and inversely proportional to the mass of the object. (F = m x a)

3. For every action, there is an equal and opposite reaction.

Edit: Neo beat me to it. Mass is usually in kilograms.

[Neo]

kilograms

[Revival]

Thanks Neo and Xantar.

I knew the 1st and 3rd laws, but I always get stuck on the second one. I also get stuck on mass in kilograms.

Xantar, I'm trying to remember what I forgot for my Physics midterm, if that makes any sense. :D

[Xantar]

The trick I use to keep all the units straight is I memorize how they are related to each other. It doesn't sound like it would work, but let me explain.

For example, F = m x a is the second law. You know that acceleration is meters per second squared, and you know that force is Newtons. A Newton is 1 kilogram x 9.8 meters per second squared (1 gravity). Knowing this, you can solve for the units of mass.

In mechanical physics, every unit can be stated in terms of the meter, the second or the kilogram. That's the way they are designed. So if you just remember how each unit relates to the basic units of measurement, you can generally figure everything out. I actually never memorized Newton's Second Law. I just knew that it had something to do with mass, force and acceleration, so I put together an equation where all the units cancel out.

It sounds complicated, and maybe it won't work for you. But it worked for me, so I thought it might be worth a try.

[Revival]

Woah, I actually understand that.

Thanks a lot! :D

[Kitana85]

EEK! I needed that too... I have physics midterms coming up too.... eek!!

[Revival]

Originally posted by Kitana85
EEK! I needed that too... I have physics midterms coming up too.... eek!!
I just had my Physics midterm.. got an 87 on it.. if you have any questions ask Neo - he did major in Physics. Also, someone else smart (like Xantar) might know.;)

[Xantar]

<-----not smart. Just well educated.

[Crazy Bastard]

Originally posted by Xantar
<-----not smart. Just well educated.

smart or well educated?what do YOU think? *Dun dun dun*

[BreakABone]

*Looks at thread*

*Writes this all down*

Hey I got to take this class next year might as well get prepared.. then again the way I'm going that year will be easy as pie with only 2 major classes

[GameKinG]

Title^

[BlueFire]

erhmm....I had to memorize this stuff last year...and I had to know it for the olympics. Another name fore the 1st law would be inirshia (Sorry, I can't remember the spelling :D).

[Xantar]

GameKinG:

This is true, but it's not unusual for high school freshmen to learn this stuff. I learned Newton's Laws in 7th grade (like I said, I was well educated), but they were still teaching it in my high school.

Even worse, some of the seniors were just starting to learn about planetary orbits...:unsure:

BlueFire:

If you'd read my post, you would have known that it's spelled "inertia." :p