| A | B |
|---|
| uniform circular motion | when an object travels in a circle at a constant speed |
| tangential velocity | the velocity in the direction that is tangent to a curved path at each point |
| tangential acceleration | the change in speed per unit time of an object as it travels in a curved path. The direction is tangent to the path at each point. |
| centripetal acceleration | the inward radial acceleration experienced by an object traveling in a circle. The direction is perpendicular to the direction of the velocity vector. |
| period (T) | the time required for an object to complete one revolution |
| frequency (f) | the number of repetitions of the motion per unit time |
| centripetal force | the term used for the force acting toward the center of the circle. The force must be applied by some external agent. |
| Newton's Universal Law of Gravitation | the force of attraction between any two objects due to their masses. The magnitude of the force is drectly proportional to the product of their masses and inversly proportional to the square of the distance between their centers. |
| circumfrence | the perimeter of a circle; distance around a circle |
| torque | the measure of the effectiveness of a force in producing rotation of an object about an axis |
| second condition of equilibrium | when the sum of all torques acting on an object about any axis perpendicular to the plane of the forces equals zero |
| machine | devices used to change the magnitude and/or direction of a force by changing the distance over which the force is exerted |
| ideal mechanical advantage | the advantage of a machine if the work done by friction equals zero |
| actual mechanical advantage | the advantage when the work done by friction is included |
| efficiency | the amount of useful work output divided by the amount of work input. |
