David Paste wrote:
Hello,

When writing, for example, "metres per second per second" for
acceleration, it is noted as ms^-2 (where the caret symbolises
the -2 is in superscript).

I understand that, and why, "per second per second" is "seconds
squared", but in the notation, why is it superscript minus 2? Why
not just superscript 2?

If I was ever taught this in maths lessons, the info is no longer
in my head.

Thanks in advance for any help,

David Paste.


While all (or perhaps most) of the answers posted are correct, I dont
think any quite get to the basic reason.

For that you need to look at the laws of indices.

4 = 2^2
2= 2^1
1 = 2^0
1/2 = 2 ^ -1
1/4 = 2^ -2 = 1/(2^2)



Ive use 2 for simplicity but the rules apply for other numbers.

Hopefully you can see the pattern.

If we substitute m for 2 then, in particular in the last line we get:

m^-2 = 1/(m^2) which is also 1/m * 1/m

The laws of indices €˜pop up in a number of places and can be very useful.
They are the basis of Logarithms, can be used to find HCF and LCMs, .......