Deceleration

Your answers are RIGHT!!

...except that acceleration is 2 m/s² or ms^-2 if you prefer.

It asks for the deceleration - the deceleration is 2ms^-2. There's no minus sign before the 2 because it is already clear that it is decelerating not accelerating.

No the unit of acceleration is ms^-2 this never changes! Acceleration is a vector quantity meaning that it must have direction - so if acceleration is positive (forwards in direction) then deceleration (backwards in direction) must be negative.

So I would use ^-2 all the time if I'm talking about deceleration and just the regular ² for accelaration?

nono - wrong end of stick!

The units ms^-2 and m/s^-2 are the same thing. There's no such unit that i know of "ms²".

I thought you were reffering to the fact that deceleration is usually written as negative acceleration, eg. -2ms^-2. My post was saying that since it is already stated that it is deceleration, there is no need for the "-" in front of the 2: this one >2ms^-2 not 2ms^{- this one>2}

I realise it was unclear - apologies.

Ohh so use the same units for both of them yeah I get it now.. it's just in class we've been taught that acceleration is m/s² rather than m/s^-2.

Dammit - there's still a little point here:

unit of acceleration and deceleration are the same (echoing trolley)

This unit can be written as

ms^-2

OR

m/s²

Absolutely and categorically NOT

m/s^-2

Aha!!! *moment of realisation* ... *cements into mind*