Physics A U1-4 Language Development

centripetal acceleration

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

tangential speed

the linear speed of any object moving along a circular path and directs tangent to the circle

orrery

mechanical model of the solar system

rotation

circular movement of an object around an axis of rotation; movement along circular path

Ellipse

a flattened circle or oval that has two centers called the foci.

Kepler's first law of planetary motion

Planets move around the Sun in elliptical orbits with the Sun at one of the foci.

Kepler's second law of planetary motion

As a planet moves around its orbit, it sweeps out equal areas in equal times

Kepler's Third Law of Planetary Motion

period (T) squared of a planet is directly proportional to the cube of its average distance (r) from the sun

frequency

the number of complete rotations/revolution in a given time

period

the time to complete a full rotation/revolution

solar system

the collection of eight planets and their moons in orbit around the sun, together with smaller bodies in the form of asteroids, meteoroids, and comets.

Kuiper belt

A region of the solar system that is just beyond the orbit of Neptune and that contains small bodies made mostly of ice

outer planets

Jupiter, Saturn, Uranus, & Neptune. Called Gas Giants.

inner planets

Small, rocky planets that orbit closest to the sun including Mercury, Venus, Earth, & Mars

Revolution

The movement of an object around another object

work

one way to transfer energy; force causes displacement of an object (measured in J)

kinetic energy

object's energy because of its motion (measured in J) (1/2 x mass x speed^2)

potential energy

energy associated to position, shape, or condition

gravitational potential energy

potential energy stored in gravitational fields (mgh, measured in J)

elastic potential energy

result of deformation of an elastic object like a spring

spring constant

k - measure of a spring's resistance to being compressed or stretched

mechanical energy

combination of kinetic and potential energy

power

rate of work done or energy transformed (work/time or force x speed, measured in W)

Joule

unit of energy

Watt

SI unit of power

rate

a magnitude or frequency relative to a time unit OR any quantity divided by time

Work - Kinetic Energy theorem

net work done by all forces equal to object's KE change (network = kinetic final - kinetic initial)

force

action exerted onto an object that may change its state of motion; a push or a pull; measured in Newtons

inertia

object's resistance to move

Newton's 3 Laws of Inertia
1) in the absence of net force, a body will preserve its state of motion
2) acceleration directional proportional to net force and is inversely proportional to mass
3) for every action, there is a equal and opposite reaction

net force

vector sum of all the forces that act upon an object

equilibrium

net force = 0; all forces balance out to zero

weight

mass x free fall acceleration;

normal force

supporting force, perpendicular to the surface

static friction

force that resists the initiation as a sliding motion

kinetic friction

force opposes the movement of two surfaces that are in contact

coefficient of friction

force of friction / normal force; a number that depends on the type of surfaces that are in contact

momentum

mass x velocity; inertia in motion

impulse

force x time; or change in momentum

Impulse - change in momentum theorem

F*t = change in mv

collision

two objects bump into each other

elastic collision

total momentum and KE are conserved

inelastic collision

a collision in which the total kinetic energy of the colliding bodies or particles is not the same after the collision as it was before (as opposed to elastic collision); momentum is conserved but KE is not conserved

perfectly inelastic collision

objects stick together after colliding; the maximum amount of kinetic energy has been lost

explosions

a special type of collision. It is a perfectly inelastic collision that seemingly happens in reverse. Before the 'collision', all objects are stuck together. After the 'collision', all objects are moving apart from one another.

Newton's First Law of Motion

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.

Newton's Second Law of Motion

F=ma; where a and F have the same direction

Newton's Third Law of Motion

Every action has an equal and opposite reaction.

range (of a projectile)

distance between the launch point and where the projectiles hits the ground

projectile (motion)

the motion of an object thrown or projected into the air, subject to only the acceleration of gravity

frame of reference: a set of criteria or stated values in relation to which measurements or judgments can be made.

a set of criteria or stated values in relation to which measurements or judgments can be made: positive - negative
right - left
up - down
north - south
east - west

displacement

change in position (measured in m)

average velocity

total displacement divided by time during displacement occurrence (measured in m/s)

instantaneous velocity

velocity at a specific point in time

acceleration

change in velocity; velocity rate changes (change in velocity/time change; m/s^2)

free fall

motion of an object when only the force due to gravity is acting on body

accuracy

how close a measurement is to the corrected or accepted value of quantity

precision

the degree of exactness of a measurement

hypothesis

can be tested or researched

model

plan or representation

controlled experiment

An experiment in which you change one thing (independent variable) and measure how this change affects something else (dependent variable).