Chapter 4: Newton's Second Law of Motion

Force

push or pulled measured in Newtons

Friction

The resistive force that opposes the motion or attempted motion of an object either past another object with which it is in contact or through a fluid.

Mass

The quantity of matter in an object. More specifically, it is the measure of the inertia or sluggishness that an object exhibits in response to any effort made to start it, stop it, deflect it, or change in any way its state of motion.

Weight

The force upon an object due to gravity, *mg*. (More generally, the force that an object exerts on a means of support.)

Kilogram

The fundamental SI unit of mass. One kilogram (symbol kg) is the mass of 1 liter (1 L) of water at

Newton

The Standard International (SI) unit of force. One newton (symbol N) is the force that will give an object of mass 1 kg an acceleration of

Newton’s second law

The acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object.

Terminal speed

The speed at which the acceleration of a falling object terminates because air resistance balances gravitational force.

Terminal velocity

Terminal speed with direction specified.