This topic is in the 'Newton's 2nd Law' section. This section helps explain and predict how things move when they are pushed or pulled. It turns out that all you need to know in order to figure out how an object will accelerate, is the object's mass, and the total force pushing or pulling on the object. The trickery comes up when you have to figure out what forces are actually acting on an object, where the object ends and begins, and how different forces combine to give you the total force acting on the object. You'll see a bunch of tutorials in this section covering many of the basic and more tricky problems that you'll come across, so check them out!