Unit 3 Vocabulary Physicss

spring forces

-Applied force proportional to distance spring is compressed or stretched -Internal restoring force arises, returning spring to original shape -Restoring force also proportional to stretched or compressed distance

Friction

A force that opposes motion between two surfaces that are in contact

Weight

A measure of the force of gravity on an object

Force

A push or pull exerted on an object

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

air resistance

Fluid friction acting on an object moving through the air

Newton's Third Law

For every action there is an equal and opposite reaction

Newton's Second Law

Force = mass x acceleration

unbalanced forces

Forces that produce a nonzero net force, which changes an object's motion

kinetic friction

Friction between moving surfaces

static friction

Friction that acts on objects that are not moving

net force

The combination of all forces acting on an object

tangential velocity

The speed of an object at a point as it moves around the circumference of a circle.

Inertia

The tendency of an object to resist a change in motion

free-body diagram

a diagram showing all the forces acting on an object

centripetal force

a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.

tension forces

a force that pulls on a material and stretches it apart

Inverse relationship

a relationship in which one variable decreases when another variable increases

direct relationship

a relationship in which one variable increases with an increase in another variable

Equilibrium (=balanced forces)

a state in which opposing forces or influences are balanced.

Newton (unit)

a unit of force equal to the force that imparts an acceleration of 1 m/sec/sec to a mass of 1 kilogram

Centipetal acceleration

acceleration of an object toward the center of a curved or circular path

gravitational force

an attractive force that acts between any two objects

Four fundamental forces

gravitational, electromagnetic, strong nuclear, weak nuclear

Universal Law of Gravitation

one of Newton's three rules of motion; it explains that planetary bodies continue in elliptical orbits around the sun because every object in the universe is attracted to every other object by a force called gravity.

mass

the amount of matter in an object

terminal velocity

the constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity

normal force

the force perpendicular to a surface that prevents an object from falling through the surface

coefficient of friction

the ratio of the force of friction to the normal force acting between two objects

Period (T) in a circular motion

time taken for one complete circle