Chapter 12 Key Terms:

Coefficient of friction	number that serves as an index of the interaction between two surfaces in contact.
Coefficient of restitution	number that serves as an index of elasticity for colliding bodies.
Friction	force acting over the area of contact between two surfaces in the direction opposite that of motion or motion tendency.
Impact	collision characterized by the exchange of a large force during a small time interval.
Impulse	product of a force and the time interval over which the force acts.
Kinetic energy	energy of motion, calculated as 1/2 mv2
Kinetic friction	constant-magnitude friction generated between two surfaces in contact during motion.
Linear momentum	quantity of motion, measured as the product of body's mass and its velocity.
Maximum static friction	maximum amount of friction that can be generated between two static surfaces.
Normal reaction force	force acting perpendicular to two surfaces in contact.
Perfectly elastic impact	impact during which the velocity of the system is conserved.
Perfectly plastic impact	impact resulting in the total loss of system velocity.
Potential energy	energy by virtue of a body's position or configuration calculated as the product of weight and height.
Power	rate of work production that is calculated as work divided by the time during which the work was done.
Strain energy	capacity to do work by virtue of a deformed body's return to its original shape.
Work	calculated as force multiplied by the displacement of the resistance in the direction of the force.