Question

for newton's laws, do you refer to acceleration as m/s^2 or N/kg?

Answer 1

don't you use N/kg for gravity also?

Answer 2

yes gravity is just a special type of acceleration.

Answer 3

so in newton's laws, you go for a=N/kg instead the m/s^2?

Answer 4

yes because m/s^2 is just units. whereas N/kg is actually a variable representation of acceleration.

Answer 5

is 1 N/kg equal to 1 m/s^2?

Answer 6

wait actually I'm sorry for some reason I was thinking F/m. both are units that mean the same thing.

Answer 7

so really use can use either to represent accleration, but typically we use m/s^2 to represent acceleration.

Answer 8

For Newtons second law the units would be m/s^2

Answer 9

is this for a homework question or are you just trying to understand units better?

Answer 10

understanding the units, because im not sure what units to put after i find the acceleration?

Answer 11

use m/s^2

Answer 12

N/kg is odd, butt yes it means the same thing.

Answer 13

think about velocities unites, we use m/s for velocity, so to keep it consistent use m/s^2 for acceleration.

Answer 14

alright!thank you
and do you know what 1 newton is equivalent to?:s

Answer 15

yes

one newton = (kgm)/s^2

Answer 16

okay thanks alot!

Answer 17

no problem.

Answer 18

See if you look at g as acceleration due to gravity.. then you normally use m/s^2.. cause even if its acceleration due to gravity.. its none the less acceleration and that has to be its SI units..

However.. there is another TOTALLY DIFFERENT way to look at g.. and that is called as gravitational field intensity.. .meaning.. how strong is the field of gravity due to earth (or for that matter any mass).. when you mean THAT way.. you usually say g = N/kg.. meaning you are saying.. how much force a UNIT mass would experience in a gravitational field...

so bottom line

if i said g = 9.8m/s^2... it basically says how much acceleration i would get at that point ..

if i said g = 9.8 N/kg.. it means how much force is experienced by a unit mass kept at that point..

so even though they have the same physical dimensions.. they are two VERY different concepts!! and hence we use those different units!

Answer 19

First thing: there is no difference between N/kg and m/s², so both are ok.

Acceleration is a kinematic concept in the first place. So it is more logical to use m/s²
Even if N's 2nd law did not exist, and the unit newton had not been defined, you could still work with accelerations in m/s².

When you first encounter g, it is seen as the ratio of a force by a mass as you hang a mass on a spring, so it is logical to use N/kg to define it.
But then you realise an object in free fall has an acceleration equal to g as well, and then the natural unit becomes m/s².


It is the same with other quantities, and it is sometimes a cultural point of view. In France, all electric fields are given in V/m, but I think I have seen a different (but same) unit on this forum, though I cannot remember which one it was, maybe N/C.