Today, Ninjas are getting a chance to mess around with a physics engine called Box2D in a side-scrolling ScratchX game that sees them pushing over haybales and avoiding swinging ramps with a monster truck! What will happen if we give our truck really bouncy tyres or give one less grip or even change gravity itself!
To give you a bit of a head-start in the game you can download a partially-made version of the game here: Gravity_Density_and_Bounce_Ninja_Version.sbx.
The final version should like a bit like this one: Gravity_Density_and_Bounce_Final_Version.sbx.