| Inertia |
The tendency of matter
to remain at rest (or keep moving in the same direction) unless affected
by some outside force or forces. When you wind up a top, you are storing
energy in it. As the top is thrown, the energy is slowly released and the
itertia keeps the top moving until acted upon by outside forces. In the
case of the top, these forces are gravity and friction. |
| Gravity |
The force that tends
to draw all bodies in the earth's sphere toward the center of the earth. |
| Friction |
The resistance to motion of surfaces
that touch. In the spinning top there are two types of friction: direct
friction of the tip with the spinning surface and air friction
with the surface of the top. The sharpness of the tip, the smoothess of
the spinning surface, and smoothness of the top's surface determine the
amount of friction the spinning top will encounter. The less friction,
the longer the spin.
|
| Centrifugal
Force |
Forces tending to
make rotating bodies move away from the center of rotation. This principle
states that a body (the top) rotating rapidly about its axis will tend to
resist outside influences (gravity). Actually, a top remains upright because
centrifugal force pulls inward on the top, keeping the vertical axis of
the top perpendicular to the horizontal axis of the ground. |