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Science Final
N/A
134
Science
8th Grade
06/12/2010

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Cards

Term
What is energy?
Definition
the ability to do work or cause change
Term
What is the unit of measurement for energy?
Definition
Joules (J)
Term
What is kinetic energy?
Definition
the energy an object has due to its motion
Term
What is potential energy?
Definition
stored energy
Term
What is gravitational potential energy?
Definition
potential energy due to an object's height
Term
What is elastic potential energy?
Definition
potential energy that is associated with objects that can be stretched or compressed
Term
What kind of energy does natural gas have?
Definition
chemical energy
Term
What kind of energy does hot water have?
Definition
thermal energy
Term
What kind of energy is created from friction?
Definition
thermal energy
Term
What kind of energy happens when a turbine spins?
Definition
kinetic energy
Term
What kind of energy does a spinning turbine create?
Definition
electrical energy
Term
What are the 7 types of electromagnetic energy?
Definition

1. radio waves

2. microwaves

3. infared rays

4. visible light

5. ultraviolet rays

6. x-rays

7. gamma rays

Term
What is the Law of Conservation of Energy?
Definition
energy cannot be created or destroyed
Term
What is force?
Definition
a push or a pull
Term
Do forces act by themselves?
Definition
no
Term
What happens when two forces act in the same direction?
Definition
they add together
Term
What happens when two forces act in opposite directions?
Definition
it is like adding a positive and negative number
Term
What is inertia?
Definition
the tendency of an object to resist a change in motion
Term
How does mass relate to inertia?
Definition

increase the mass, increase the inertia

decrease the mass, decrease the inertia

(direct relationship)

Term
What is weight?
Definition
the force of gravity on a person or object at the surface of a planet
Term
What is the formula for acceleration?
Definition
net force / mass
Term
How do force and mass affect acceleration?
Definition
force and mass have a direct relationship on acceleration
Term
What is friction?
Definition
the force that 2 objects exert on each other when they rub against each other
Term
List and describe 3 kinds of friction.
Definition

1. static friction- not moving

2. sliding friction- objects sliding over each other

3. rolling friction- an object rolling across a surface

Term
What is free fall?
Definition
when gravity is the only force acting on a falling object
Term
What is air resistance?
Definition
a  type of fluid friction that occurs when object fall through air
Term
Do object attract or repel when affected by gravity?
Definition
attract
Term
What is momentum?
Definition
a characteristic related to the mass and velocity
Term
How do you calculate momentum?
Definition
momentum = mass * velocity
Term
How do you increase the momentum of an object?
Definition
increase the mass or increase the velocity
Term
What is the Law of Conservation of Momentum?
Definition
the total momentum of objects that interacts does not change
Term
What is Newton's first law of motion?
Definition
an object at rest will remain at rest, and an object in motion will remain in motion, unless a force acts upon it
Term
What is Newton's second law of motion?
Definition
acceleration depends on the objects mass and on the net force acting on the object
Term
What is Newton's third law of motion?
Definition
if one object exerts a force on another object, then the second object exerts an equal force in the opposite direction
Term
What kind of force causes an object to move in a circle?
Definition
centripetal force
Term
How do you increase friction?
Definition
use sand on ice
Term
How do you decrease friction?
Definition
add oil or lubricant
Term
What is the metric unit for force?
Definition
newton (N)
Term
What is the metric unit for energy?
Definition
joules (J)
Term
What is the metric unit for momentum?
Definition
kg/m/s
Term
What is the metric unit for speed?
Definition
m/s
Term
What is the metricd unit for acceleration?
Definition
m/s^2
Term
What is the metric unit for weight?
Definition
newtons (N)
Term
What is the metric unit for pressure?
Definition
pascals (Pa)
Term
What is the metric unit for work?
Definition
joules (J)
Term
What is the metric unit for power?
Definition
watt (W)
Term
What is the metric unit for frequency?
Definition
hertz (Hz)
Term
What is a balanced force?
Definition
equal forces acting on one another in opposite directions
Term
What is unbalanced force?
Definition
when there is a net force acting on an object
Term
What is an example of a balanced force?
Definition
arm wrestling
Term
What is an example of an unbalanced force?
Definition
two people pushing a box the same way
Term
What is the relationship of pressure to area?
Definition

increase area, decrease pressure

decrease area, increase pressure

(indirect relationship)

Term
What is the relationship of pressure to depth?
Definition

increase depth, increase pressure

decrease depth, decrease pressure

(direct relationship)

Term
What is the relationship of pressure to elevation?
Definition

increase elevation, decrease pressure

decrease elevation, increase pressure

(indirect relationship)

Term
What is Bernoulli's principle?
Definition
the faster a fluid moves, the less pressure the fluid exerts
Term
What is Archimedes principle?
Definition
the buoyant force acting on an object is equal to the weight of the fluid the object displaces
Term
What is Pascal's principle?
Definition
when force is confined to a contained fluid, the pressure is spread equally to all parts of the fluid
Term
What is buoyancy?
Definition
the ability to float
Term
What principle explains buoyancy?
Definition
Archimedes principle
Term
How do you know when an object is in motion?
Definition
when its distance from another object is changing
Term
What is the formula for speed?
Definition
speed = distance / time
Term
What is velocity?
Definition
the speed in a given direction
Term
What 2 things are needed to know the velocity of an object?
Definition
speed and direction
Term
What is acceleration?
Definition
the rate at which velocity changes
Term
What are three things that can happen to change acceleration?
Definition

1. increase the speed

2. decrease the speed

3. change the direction

Term
What is speed?
Definition
the distance an object travels per unit of time
Term
What is instantaneous speed?
Definition
the rate an object is moving at any given instant
Term
What is average speed?
Definition
total distance / total time
Term
What is a reference point?
Definition
a place or object used for comparison to determine if something is in motion
Term
What does a horizontal line represent on a distance vs. time graph?
Definition
the object is standing still (not moving)
Term
What does constant speed look like on a graph?
Definition

a straight, diagonal line upward

 

       /

    /

  /

/

Term
How do you know that the planets and the moon accelerate?
Definition
They move in a circular path which means they are changing direction.
Term
What does a straight line represent of an acceleration graph?
Definition
the acceleration is constant
Term
What is absolute zero?
Definition
when no more thermal energy can be removed from an object
Term
if you increase the amount of particles in an object, what happens to the thermal energy?
Definition
it increases
Term
In what direction does thermal energy and heat move?
Definition
from a warmer object to a cooler object
Term
What is conduction?
Definition
when heat is transferred from one particle of matter to another without the movement of matter
Term
What is convection?
Definition
when heat is transferred by the movement of currents within a fluid
Term
What is radiation?
Definition
when energy is transferred by electromagnetic waves
Term
What is a refrigerator?
Definition
an object that transfers thermal energy from inside it to the room outside
Term
What is a heat engine?
Definition
an object that transfers thermal energy to mechanical energy
Term
For work to happen...
Definition
an object must move some distance due to force
Term
What is the formula for work?
Definition
work = force * distance
Term
What is a machine?
Definition
an object that changes the amount of force you exert
Term
What are the 6 simple machines?
Definition

1. incline plane

2. screw

3. lever

4. pulley

5. wheel and axle

6. wedge

Term
What is the efficiency of an ideal machine?
Definition
100%
Term
What is a compound machine?
Definition
two or more simple machines combined together
Term
What is a fulcrum?
Definition
the fixed point on a lever
Term
Do unlike charges attract or repel?
Definition
attract
Term
Do like charges attract or repel?
Definition
repel
Term
What is static discharge?
Definition
the loss of static electricity on the surface of an object
Term
What is voltage?
Definition
causes charges to move in a circuit
Term
How does an electric current flow?
Definition
through the path of least resistance
Term
What is Ohm's Law?
Definition
resistance = votage / current
Term
What is a conductor?
Definition
a material that conducts electricity easily
Term
What is an insulator?
Definition
a material that doesn't conduct electricity easily
Term
What is a magnet?
Definition
a material that contains iron and creates charges
Term
What is magnetic force?
Definition
the attraction or repulsion of magnetic material
Term
What is magnetic field?
Definition
the area around a magnet where magnetic force exsists
Term

What is the difference between Earth's geographic north pole and Earth's magnetic north pole.

 

Definition
The geographic north pole is located in the northern hemisphere, at the center of earth's rotation.  Earth's magnetic field changes over time so the magnetic north pole is always changing.
Term
What does it mean if the lines of a magnetic field are close together?
Definition
there is a strong magnetic field
Term
What does it mean if the lines of a magnetic field are far apart?
Definition
there is a weak magnetic field
Term
What is a wave?
Definition
a disturbance in matters that transfers energy
Term
How do waves travel?
Definition
in a straight line
Term
What is a transverse wave?
Definition
a wave where particles move perpendicular to the motion of a wave
Term
What is a longitudinal wave?
Definition
a wave where particles move parallel to the motion of the wave
Term
What is a mechanical wave?
Definition
a wave that require a medium to travel through
Term
What is amplitude?
Definition
how high or low a wave moves from its rest posistion
Term
What is wavelength?
Definition
the distance between 2 like point on a wave
Term
What is a compression?
Definition
part of a longitudinal wave where material is close together
Term
What is a crest?
Definition
the high point of a transverse wave
Term
What is a trough?
Definition
the low point of a transverse wave
Term
What is a rarefaction?
Definition
the part of a longitudinal wave where material is spread apart
Term
What is a node?
Definition
a point where two waves meet and the amplitude is zero
Term
What is an antinode?
Definition
the point where two waves meet and the amplitude is at its maximum point
Term
What is reflection?
Definition
when energy bounces off an object
Term
What is refraction?
Definition
when energy bends or changes sped due to entering a new medium
Term
What is constructive interference?
Definition
two waves interacting and creating more energy
Term
What is destructive interference?
Definition
two waves interacting and reducing the amount of energy
Term
What kind of medium do electromagnetic waves require to travel?
Definition
no medium
Term
Where can electromagnetic waves travel?
Definition
everywhere
Term
What is the electromagnetic spectrum?
Definition
the range of electromagnetic waves from longest wavelength to shortest wavelength
Term
What is the formula for work?
Definition

force * distance

(J)

Term
What is the formula for speed?
Definition

distance / time

(m/s)

Term
What is the formula for frequency?
Definition

speed / wavelength

(Hz)

Term
What is the formula for acceleration?
Definition

final velocity - initial velocity / time

(m/s ^2)

Term
What is the formula for momentum?
Definition

mass * velocity

(kg*m/s)

Term
What is the formula for pressure?
Definition

force / area

(Pa)

Term
What is the formula for density?
Definition

mass / velocity

(g/cm ^3)

Term
What is the formula for power?
Definition

voltage * current

(W)

Term
What is the formula for kinetic energy?
Definition

1/2 * mass * velocity

 

Term
What is the formula for potential energy?
Definition
weight * height
Term
What is the formula for the change in energy?
Definition

mass * specific heat * change in temperature

(J)

Term
What is the formula for energy?
Definition

power * time

(kw hr.)

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