|WHY DO WE NEED TO PUSH THINGS
TO GET THEM TO MOVE?
Things don't start moving by themselves. If something is at rest, you have to push it to get it going. For a push of a given size, some objects will move more easily than others. Inertia is a measure of how much something resists being put into motion. Mass is a measure of inertia. The more massive an object is, the harder you have to push to get it moving.
|WHAT ABOUT MAKING SOMETHING ROTATE?
To get something to rotate, a twisting force has to be used. But it is more than just the mass that determines how hard it is to rotate something. It also matters how far that mass is from the point around which you are trying to rotate. If most of the mass is close to the center of rotation, it is easier to make it rotate. For example, a disk will roll more easily than a ring with the same mass and size.
|"I'm sure that of all of the
home runs I hit, at least half
of them came when I was
choking up slightly."
|When the pitcher is bringing the heat, Megan gets a jump on the ball by choking up on her bat.|