# Science 2nd semester exam Jackson

## 83 terms

### speed

how fast you go
(formula) distance divided by time

### velocity

speed with a direction
(formula) distance divided by time

### acceleration

the change in velocity over time
(formula) final velocity-original velocity divided by time

### inertia

resistance to motion, affected by mass of an object

### newton's first law of motion

an object at rest or in motion will stay that way unless acted upon by an outside (net) force, a.k.a. law of inertia

### newton's second law of motion

a net force on an object will cause it to accelerate in the direction of the force (formula) mass x acceleration (unit) newton

### newton's third law of motion

for every action force there is an equal and opposite reaction force, a.k.a. action-reaction law

### momentum

inertia in motion, affected by mass and velocity, (formula) mass x velocity, (unit) kg m/s

### gravity

attraction between two objects due to their mass, affected by the mass of the objects and the distance between them

### centripetal force

the force towards the center of a curved path that acts on an object

### centripetal acceleration

acceleration towards the center of a curved or circular path

### free fall

where the only force on a falling object is gravity, air resistance- upward force on a falling object due to friction of the air

### terminal velocity

maximum velocity reached by a falling object, air resistance- gravity's pull

### projectile motion

the curved path in the air taken by a projectile, affected by ...

### mass

the amount of matter in an object

### weight

gravity's pull on an object caused by a force

### work

transfer of energy through motion, for work to occur it must be in motion and the motion must be in the same direction of the force, (formula) force x distance, (unit) joules

### power

how fast you can do work, (formula) work divided by time, (unit) joules

### machine

anything that makes your work easier

### 4 ways machines make work easier

increases force, increases distance the force travels, changes the direction of the force, makes it go faster

### compound machine

a machine that is made up of several simple machines

### effort force

force applied to the machine

### resistance force

force placed on an object by the machine

### lever

a rigid bar that pivots or turns around a fulcrum

### 5 major parts of a lever

resistance force, resistance arm, effort force, effort arm, fulcrum

### first class lever

fulcrum in the middle, (examples) scissors, hammer, seesaw

### second class lever

resistance in the middle, (examples) nut cracker, wheelbarrow

### third class lever

effort in the middle, (examples) tweezers, broom, bat

### pulley

a grooved wheel with a rope or chain moving through it

### fixed pulley

changes the direction of the force, ma of 1, (examples) flagpole, blinds

### moveable pulley

changes the direction of the force and increases the force, ma of 2, (example) crane

### block and tackle pulley

changes the direction of the force and increases the force, ma- count number of ropes except one going down, (examples) sailing ships, cranes

### efficiency

how much useful work a machine can do, (formula) work in divided by work out x 100, (unit) joules

### wave

a repeating disturbance that transfers energy through matter or space

### wave speed

how fast the wave goes, (formula) frequency x wavelength, (unit) m/s

### reflection

a wave bounces off a surface

### diffraction

a wave bends around a corner

### refraction

wave changes speed as it changes from one medium to another

### interference

when waves combine and overlap

### white

all colors are reflected

### black

all colors are absorbed

### why do we see red

because all wavelengths of color are absorbed except red

### pitch

how high or low a sound is

### frequency

how many waves can occur in one second, (unit) hertz

### sound

compression waves caused by a vibrating object

### resonance

when energy causes a material to vibrate at is normal frequency

### doppler effect

the change in pitch of a sound due to movement

### relationship between pitch and frequency

the higher the pitch, the higher the frequency

### destructive interference

waves subtract from each other

top of the wave

### trough

bottom of the wave

### amplitude

height of the wave

### wavelength

the length of the wave from two of the same parts of the wave

### proteins

made up of amino acids, used in body for structure, enzymes, and energy (last resort), (examples) hemoglobin, muscle, and enzymes

### carbohydrates

made up of saccharides, used in body for structure, and energy (first), (examples) sugar, starches

### lipids

made up of fatty acids, used in body for structure, hormones, and energy (second), (examples) fats, oils, waxes

### nucleic acids

made up of nucleotides, used in body to store and transfer information, (examples) RNA and DNA

contain carbon

### inorganic molecules

do not contain carbon

### hydrocarbon

made up of hydrogen and carbon

### saturated hydrocarbon

contains only single bonds

### unsaturated hydrocarbon

contains at least one double or triple bond

### substituted hydrocarbon

one or more hydrogen atoms are replaced by other things

### organic acid

replaces a hydrogen atom with -COOH

### alcohol

replaces a hydrogen atom with -OH

heat energy

light energy

### chemical energy

energy found in chemical bonds

### mechanical energy

energy of motion made up of kinetic energy and potential energy

### electrical energy

energy from electron movement

### nuclear energy

energy from the nucleus of an atom

### kinetic energy

energy of motion, affected by mass and velocity, (formula) mass x velocity squared divided by 2, (unit) joules

### potential energy

energy of position or stored energy

### elastic potential energy

energy stored by an object that can compress or stretch, (examples) spring, bungee cord, rubber band

### chemical potential energy

energy stored in chemical bonds, (examples) food, fossil fuels

### gravitational potential energy

energy stored by anything that can fall, affected by mass, acceleration of gravity, and height, (formula) mass x height x 9.8 m/s squared, (unit) joules

### heat

the movement of thermal energy from an area of higher temperature to an area of lower temperature

### temperature

measures the average kinetic energy of the particles in an object

### conduction

transfer of heat through contact

### convection

transfer of heat by moving currents in matter