Question about Kindle Fire charger (also applicable to other tablets/devices)

With our new Kindle Fire, we received a USB charging cord (i.e. to plug the Kindle directly into a USB port on our computer), but not the wall/AC adapter itself (if you use an iPhone or iPad, it's very similar to the setup of those charging cords).

Now, I know it's only $20, but we already have a lot of iPhone/iPad cords, not to mention chargers.

So I was wondering... can one [safely] use an iPhone or iPad wall/AC adapter to charge a Kindle Fire?

In other words, I'd plug the iPad's AC adapter into a wall outlet, and then plug the Kindle's charging cable into the USB outlet of the iPad's AC adapter.

Specs from Amazon's original Kindle Fire Replacement AC Adapter:

Specs from the current Amazon Kindle PowerFast for Accelerated Charging:

The specs for the Apple's various iDevice wall/AC adapters can be found here.

 

I use an HP Touchpad or Archos 80G9 charger for my son's Kindle and he uses my daughter's iPod touch charger when he visits his mother.

 

My gut instinct was to go ahead and use the iPhone or iPad adapters/bricks (since they have a USB port on them, which I assumed was fairly universal).

That said, they're not exactly cheap toys, so I didn't want to burn it up using a charger that was either too powerful, or not powerful enough.

I remember that Apple has said iPhone owners can use their iPad charger (even though it puts out 2x the wattage), because the iPhone has "smart charger" technology which allows it to only accept as much charge as it needs (5w).

I didn't want to extrapolate that to Amazon, however, because Apple has an "existing user base" motivation to ensure iPhone/iPad charger interchangeability, and Amazon has no such motivation.

I looked a number of places online, and while I didn't see the question had been asked too many times, the answers were all over the place ("Yes you can," "No you can't").