Physics Unit 2– Forces and Circular Motion

Force (F)

The cause of an acceleration, or the change in an object’s velocity.

Free-Body Diagram

A diagram of the objects involved in a situation and the forces exerted on the objects.

Newton’s First Law

An object at rest remains at rest, and an object in motion continues in motion with constant velocity unless the object experiences a net force.

Inertia

The tendency of an object to maintain its state of motion.

Net Force (\sum F)

The total force resulting from a combination of forces on an object; also called the total force.

Newton’s Second Law

The net force acting on an object is equal to the product of the object’s mass and its acceleration.

Newton’s Third Law

If two objects interact, the magnitude of the force exerted on object 1 by object 2 is equal to the magnitude of the force simultaneously exerted on object 2 by object 1, and these two forces are opposite in direction.

Action-Reaction Pair

A pair of simultaneous equal but opposite forces resulting from the interaction of two objects.

Weight (F_{W})

The magnitude of the force of gravity acting on an object.

Normal Force (F_{N})

A force exerted by one object on another in a direction perpendicular to the surface of contact.

Gravitational Force

The mutual force of attraction between particles of matter.

Tangential Velocity

The velocity of an object moving in a circle. It is always directed tangent to the circle.

Centripetal Force

Force directed toward the center of a circular path. Examples: tension, friction, gravity, push.

Centripetal Acceleration

Acceleration directed toward the center of a circular path.

Period

The amount of time it takes for an object to complete 1 full cycle.