For a year probably I've never figured out how to make a good physics engine. I've seen some great ones but some I haven't fully understood. Can someone please just post an image of an advanced yet easy to understand physics engine with velocity Thanks!

You need to be a bit more specific. Do you want something that uses proper physics equations or an approximation like a game?

UnofficialCoder has one put together using simple algebra formulas (h = -16*t^2 + v*t + s)

You can find it here.

Also, 2 built in sprites (from 1.4) are made just for gravity and friction related velocity (Physics terms!)

I think you are looking for diesel, two or four stroke engines…
If so, I don't know if there is an Scratch project done, but this page can help you a lot:
http://www.animatedengines.com/index.html

I'm just looking for left and right movement + jumping where you can't pass through a color (or sprite)

Better this way

Look at this
http://www.youtube.com/watch?v=4YoGkwV7D9c

turkey3 wrote:

I'm just looking for left and right movement + jumping where you can't pass through a color (or sprite)

Look in the sticky for this forum there are lots of little scripts in there for doing just that sort of thing.