# Lachman's Final

## 82 terms · Everything from the study guide.

### speed

distance an object travels per unit of time

### average speed

calculated by dividing the total distance by the total time of travel

### displacement

distance & direction of an object's position from the origin

### velocity

includes speed and direction of motion

### acceleration

occurs when an object changes its speed, direction, or both

### inertia

the tendency of an object to resist change in motion

### force

push or pull that one body exerts onto another

### balanced forces

forces on a body that are equal in size and opposite in direction

### instantaneous speed

speed at any given time

### friction

force that opposes motion between two touching surfaces

### weight

the gravitational force exerted on an object

### momentum

the product of the mass of an object and its velocity

### static friction

exists between two surfaces that are not moving past each other

### gravity

when two masses exert an attractive force on each other

### chemical potential

energy stored in the chemical bonds between atoms

### gravitation potential

depends on the mass of the object, its height above the ground, and its acceleration due to gravity

### joule

SI unit of energy

### kinetic

energy in the form of motion

### mechanical energy

the sum of the potential and kinetic energy in a system

### elastic potential

energy stored by something that can stretch or compress

### heat

produced by the flow of electrons through a material

### insulator

material that does NOT allow electrons to easily flow through it

### resistance

tendency of a material to oppose the flow of electrons through it

### parallel circuit

type of circuit that mas more than one branch for current to flow

### power

equals current X voltage difference

### voltage

the "push" that cause charge to move in a circuit

### series circuit

circuit with only one path for current to flow

### transformer

can be used to increase or decrease the voltage in alternating current (AC)

### electrical generator

converts mechanical energy into electrical energy

### turbine

a large wheel that rotates when pushed by water, wind, or steam

### poles

region where the magnetic forces of a magnet is strongest

### direct current

batteries produce this type of electron flow

### galvanometer

device that uses and electromagnet to measure electric current

### electromagnetic induction

a generator works based on the principle

### alternating current

reverses the direction of current flow in a regular way

### electromagnet

made of a soft iron core surrounded by loops of current-carrying wire

### fossil fuel

includes coal, petroleum, and natural gas

### photovoltaic cell

converts light energy into electricity

### petroleum

crude oil that is highly flammable former by decaying organisms

### nonrenewable

energy source that cannot be replaced as fast as it used

### biomass

includes organic matter such a wood and rice hulls

### geothermal

thermal energy form the earth that can be used to generate electricity

### hydroelectric

electrical energy produced from the energy of moving water

### constructive interference

when two or more waves overlap and combine to form a new wave

### diffraction

the bending of a wave as it changes speed when passing from one medium to another

### wavelength

measured from crest to crest or trough to trough in a transverse wave

### medium

matter that a wave travels through

### transverse

matter moves back and forth at right angles to the direction the wave travels

### compressional

an example of this type of wave is sound

### frequency

the number of wavelengths that pass a given point each second

### rarefraction

the less dense region of a compressional wave

### amplitude

relates directly to the energy carried by a wave

### sonar

uses reflected underwater sound waves to detect objects

### dB (decibels)

units used to measure the intensity of sound

### doppler effect

change of pitch or wave frequency due to a moving wave source

### acoustics

the study of sound

### ultrasonic

sound waves above the normal frequency range of human hearing

### cochlea

part of the ear that converts sound waves into nerve impulses

### resonator

hollow chamber filled with air that amplifies vibrating sound waves

### visable

portion of the electromagnetic spectrum that you can see

### infared

type of energy used to produce thermograms

### ultraviolet

the ozone layer above the earth blocks much of this radiation

### photon

particle whose energy is dependent on the frequency of the light

### x-ray

often used in medicine to produce images of the body

### electromagnetic spectrum

is composed of vibrating electrical and magnetic fields

### gamma

very high energy, short wavelength wave that can damage cells

short waves often used in communications

### coherent light

light of only one wavelength that travels with its crest and troughs aligned

### translucent

allows some light to pass through, but you cannot see clearly through it

### infared

is produced when objects become so hot that that give off light

### opaque

does not allow any light to pass through

### pigment

colored material that absorbs some colors and reflects others

### concave or diverging

lens that is thinner in the middle than at the edges

### mirror

smooth, flat surface that reflects an image

### focal length

distance from the center of lens or mirror to the point of focus

### cornea

transparent outer covering of the eye

### real image

image formed when light rays converge

### optical axis

imaginary line drawn perpendicular to the surface of a mirror or lens at its center

### retina

part of the eye that converts light images into electrical signals

### convex or converging

lens that is thicker in the middle than on the edges

### convex mirror

reflects an image that is virtual,upright, and smaller than the object