4-2-newtons-first-law-of-motion-inertia_glossary

A constant that depends on the nature of the two surfaces in contact.

Motion in a straight line at a constant speed.

A force acting on the system of interest from outside the system.

The force that opposes motion; depends on the coefficient of friction and the normal force (F_f = μN).

An external force that acts opposite to the direction of motion; a resistance to motion.

The tendency for an object at rest to remain at rest, or for a moving object to remain in motion in a straight line with constant speed.

A force acting within the system of interest; these forces are ignored when calculating a net external force.

A measure of the amount of matter in an object; determined by the number and types of atoms the object contains; independent of gravity. Expressed in kilograms.

The sum of all external forces acting on a system; if zero, the system is at rest or moving at constant velocity.

A body at rest tends to remain at rest. A body in motion tends to remain in motion at a constant velocity unless acted on by a net external force.