Physics Chapter 4 Vocab

Acceleration

the rate at which the velocity of an object changes

Force

a push or pull on an object; has both direction and magnitude and may be a contact or a field force

System

object or objects of interest than can interact with each other and the external world

Free-body diagram

a physical model that represents the forces acting on a system

Net force

the vector sum of all the forces on an object

Newton's second law

states that the acceleration of an object is proportional to the net force and inversely proportional to the mass of the object being accelerated

Newton's First Law

states that an object at rest will remain at rest and a moving object will continue moving in a straight line with constant speed, if and only if the net force acting on that object is zero

Inertia

the tendency of an object to resist a change in velocity

Equilibrium

the condition in which the net force on an object is zero

Viscosity

a fluid's resistance to flowing

Weight

the gravitational force experienced by an object

Gravitational field

a vector quantity that relates the mass of an object to the gravitational force it experiences at a given location; represented by the symbol g

Apparent weight

the support force acting on an object

Weightlessness

an object's apparent weight of zero that results when there are no contact forces pushing up on the object

Drag force

the force exerted by a fluid on the object moving through the fluid; depends on the object's motion and properties and the fluid's properties

Terminal velocity

the constant velocity of an object that is reached when the drag force equals the force of gravity

Symmetry

correspondence of parts on opposite sides of a dividing line

Interaction pair

a pair of forces that are equal in strength, but opposite in direction and act on different objects

Newton's third law

states that all forces come in pairs and that the two forces in a pair act on different objects and are equal in strength and opposite in direction

Tension

the specific name for the force exerted by a rope or a string

Normal force

the perpendicular contact force exerted by a surface on another object