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# Urgent A level Physics help! :( Watch

1. (Original post by hamza772000)

I know force in base units= kgms^-2
Exactly, so a Newton metre is just that multiplied by another unit of distance.

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2. (Original post by hamza772000)

I know force in base units= kgms^-2

Tag in the guy with numbers he should know, he's doing a maths degree.
3. Number density will be measured in m^(-3), not kg/m^3.

It is defined as the number of electrons per unit volume.

A number has no units, volume has units of m^3 - hence 1/m^3 = m^(-3)
4. (Original post by Andy98)
Exactly, so a Newton metre is just that multiplied by another unit of distance.

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so kgms^-2*m?

(Original post by Grimm Reaper)
Tag in the guy with numbers he should know, he's doing a maths degree.
Dw, it's fine Grimm

(Original post by kingaaran)
Number density will be measured in m^(-3), not kg/m^3.

It is defined as the number of electrons per unit volume.

A number has no units, volume has units of m^3 - hence 1/m^3 = m^(-3)
So number density in base units= m^-3?
5. (Original post by hamza772000)

So number density in base units= m^-3?
Well yeah?
6. (Original post by hamza772000)
so kgms^-2*m?

Dw, it's fine Grimm

So number density in base units= m^-3?
Yes, so simplifying that gives you....
7. (Original post by kingaaran)
Well yeah?
This says otherwise, no?

8. (Original post by Andy98)
Yes, so simplifying that gives you....
kgm^2s^-2?
9. (Original post by hamza772000)
This says otherwise, no?

Those all relate to the mass, number density just relates to the number

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10. (Original post by Andy98)
Those all relate to the mass, number density just relates to the number

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Oh, sorry yeah, I failed to recognise the Kg i there so it's m^-3..
11. (Original post by hamza772000)
kgm^2s^-2?
Correct

(Original post by hamza772000)
Oh, sorry yeah, I failed to recognise the Kg i there so it's m^-3..
It's OK dude, we all have our moments

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12. (Original post by Andy98)
Correct

It's OK dude, we all have our moments

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Ok, so one final time pls, 1 N m= kgm^2s^-2, 1nm= 1*10^-9? 1 mN= kgms^-2*10^-3? and 1 MN= kgms^-2*10^6, do these even make sense?

and m^-3

sorry for bothering you too much
13. (Original post by hamza772000)
Ok, so one final time pls, 1 N m= 1 kgm^2s^-2, 1nm= 1*10^-9 m? 1 mN= 1 *10^-3kgms^-2? and 1 MN= 1*10^6kgms^-2, do these even make sense?

and m^-3

sorry for bothering you too much
I've rectified the answers in the quote

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14. (Original post by Andy98)
I've rectified the answers in the quote

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Oh, I get it, love you bro thank you sooo much <3
15. 3) Nm is unit of torque derived by Force x distance, force is mass x acceleration so in base units Nm = kgm^2s^-2, nm is a nanometre, mN is a millinewton and MN is meganewton.
4) It is asking for number density so think of it as number of electrons per volume, since number of electrons has no units the base unit for it would just be m^-1.
Hope this helps.
16. (Original post by JackMorgan32)
3) Nm is unit of torque derived by Force x distance, force is mass x acceleration so in base units Nm = kgm^2s^-2, nm is a nanometre, mN is a millinewton and MN is meganewton.
4) It is asking for number density so think of it as number of electrons per volume, since number of electrons has no units the base unit for it would just be m^-1.
Hope this helps.
thanks, but it should be m^-3 as it says density, no?
17. (Original post by hamza772000)
thanks, but it should be m^-3 as it says density, no?
Correct

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18. (Original post by JackMorgan32)
3) Nm is unit of torque derived by Force x distance, force is mass x acceleration so in base units Nm = kgm^2s^-2, nm is a nanometre, mN is a millinewton and MN is meganewton.
4) It is asking for number density so think of it as number of electrons per volume, since number of electrons has no units the base unit for it would just be m^-1.
Hope this helps.
It's OK dude, it's done

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19. (Original post by hamza772000)
Oh, I get it, love you bro thank you sooo much <3
Yeah, something like that

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