when you go to type numbers into the boxes for anything, like where you would set a private variable or check a value (like where the red arrow is pointing), you can double click an object's icon to get a list of expressions.
If your object is using physics, there are Get Velocity X, and Y expressions. Although they aren't in pixels per second, it's physics's internal scale of speed.
if you need to combine these two into one speed, it would be [code:ayxlwcfm]sqrt(Sprite[Physics].VelocityX^2+Sprite[Physics].VelocityY^2)[/code:ayxlwcfm]
if the answer must be in pixels per second, then you would have to make a LastX and Last Y private variable
-----Set LastX to sprite.X;
-----Set LastY to sprite.Y;[/code:ayxlwcfm]