Relation between acceleration, mass, and net force.

1. Nov 6, 2014

avito009

As we know $$\ a= \frac {F} {m}$$
So does this equation prove that acceleration is directly proportional to the net force and inversely proportional to the mass of the object?

2. Nov 6, 2014

Yes.

3. Nov 6, 2014

nasu

It does not "prove" anything.
It just expresses mathematically a relationship between quantities, as suggested by observation and experiments.

4. Nov 7, 2014

Raptor

No.
F=ma says heavy objects need more force to move, and more force means more acceleration.
a=F/m is just a vector relation saying that acceleration is co linear with net vector F. Decrease In mass decreases the force acting on it which in turn reduces magnitude of acceleration. This is more meaningful.

5. Nov 7, 2014

I fail to see the difference. One could also argue that the first equation is a vector relation.

6. Nov 7, 2014

Raptor

Let's say you are rolling down from a mountain. Let's also assume you ate a lot of food on your way down. This increases net acceleration. But how???
The answer is FORCE. We explain this with force.

Last edited: Nov 7, 2014
7. Nov 7, 2014

I still can't understand why you disagreed with DaleSpam. Could you please elaborate on your original statement?

8. Nov 7, 2014

And by the way, acceleration of free fall is independent of mass.

9. Nov 7, 2014

Raptor

Dale was not wrong at all. I just wanted to give a more meaningful statement.
It is better to say acceleration is dependent on force than the inverse.
Force causes acceleration. You should avoid saying acceleration causes force.

10. Nov 7, 2014

Raptor

Who said you are in free fall?? Mountains are triangular. You can roll on it instead of just falling.i was just giving a hypothetical example.now mg's sine component is greater for heavier object. So acceleration in the frame of reference of mountain surface is more.

11. Nov 7, 2014

A.T.

The formula says nothing about what causes what.

12. Nov 7, 2014

A body of mass $m$ placed on a smooth slope with an angle of inclination $θ$ has an acceleration of $gsinθ$. Mass doesn't show up.

13. Nov 7, 2014

Staff: Mentor

No, not more meaningful.

If you want to find the acceleration of something, you need the net force and the mass, just like the first post stated. Saying that decreasing mass decreases the force is only true if you hold the acceleration constant.

14. Nov 7, 2014

Staff: Mentor

Which is exactly what the original post describes!

Who said that?

15. Nov 7, 2014

Even the,
$mgsinx$ - $kN$ =$ma$
$a = gsinx - kN$
$a = gsinx - kcosx$
As $N = mgcosx$ for equilibrium along perpendicular direction of plane.
N is the normal reaction.

16. Nov 7, 2014

Staff: Mentor

You are making a distinction without a difference. They are the same thing.