Just how accurate are the physics in Penumbra and in Amnesia?

[Bridge]

Do you live on planet Earth? Then you should know the answer; yes they are very accurate.

I was thinking about it as I played the game. Like when you throw an object against the wall would you get the same result irl? or would I not?

You probably wouldn't; there are too many variables to consider. However objects behave almost exactly like they would in real life, so if you were to recreate the circumstances exactly then you would probably get the same results.