8th grade science final: ALL CHAPTERS!

Distance, Length, Height

Distance, Length, Height

Meter-m

Mass

Kilograms-kg

Time

seconds-s

Speed/Velocity

meter/second-m/s

Acceleration

meter/second^2-m/s^2

Force

Newton-N

Pressure

Pascal-Pa

Energy

Joules- J

Power

Watt-W

Volume

Liter-L

Temperature

Kelvins-K

Motion

occurs when an object changes its position relative to a reference point.

Distance

How far an object has moved

Displacement

Distance and direction of an object change in position from the starting point

Speed

Distance an object travels per unit of time

Speed equation

S=d/t- Speed=distance/time

Constance Speed

Car is neither speed up or slowing down

Changing Speed

Speed is changing rate

Average Speed

Discribes speed of motion when speed is change

Average Speed eqaution

Total distance travel/total time travel

Instantaneous Speed

Speed of an object at a point in time-Right now

Changing Instantaneous speed

Speeding up or slowing down-Different at every point in time

Velocity

speed and direction of an object

Scalar and Vector

Physical variables that describe motion

Vaiables

Factors that can cause a change in the results of an experiment

Scalar

Variable that can be secifed with only one number

Example of Scalar

Temp, time, mass, density, location on a line

Vector

Variables that can be specified with more that one number

Examples of vector

force, velocity, displacement, acceleration

Ways to measure Scalar

Measure magnitude-How big, far, and fastk

Ways to measures Vector

Measure Magnitude and direction

Acceleration

Rat of change of Velocity

When a cars speed up

positive Acceleration

When a car slows down

negative acceleration

A force is a _______ or a _______

Push; Pull

ITrue or False: f you apply force it can force and to move item

True

example of applying force

Picking up a pencil

What is balanced forces

Forces that do not cause movement or change in speed

is this balance forces?

A force that is equal an opposite directio

Yes

Example of a balanced force

two people pushing in different direction on a box

------> + <------= 0

Unbalanced force

When two unequal forces are pushing in opposite direction in

Example of unbalanced forces

Two kids pushing in the same way to make the box move

---->+---->=-------->

What is inertia

The tendence of an object to resist any change in its motion

The greater the inertia the great the ______

Mass

Mass is

A dimension less quantity repressing the amount of matter in a particle

Matter is

anything that takes up space and has mass

Newton's First Law of Motion

An object will at rest (or in motion) will remain at rest (or in motion) unless acted upon by another force

Newton's Second Law of Motion

The more mass an object has the more force is need to make it move or stop

Newton's third law of Motion

For every action there is an equal and opposite reaction

Seat belts

When the car is going 20mph you are going 20mph

Wearing a seat beat-30% more like to save your life

Causes injuries instead of death

NaN3 Sodium and Nitrogen makes a .004 Second reaction

Friction:

The force that oppose the sliding motion of two surface that are touching each other

What are the source of Friction

Micro welds

Static Friction

The force that prevent two surface form sliding past---Not in motion

Sliding Friction

The force that oppose the motion of two surface sliding past ---In motion

Rolling Firction

the force between a rolling object and the surface it rolls on

Air Resistance

Opposes the motion of an object falling through the air

Terminal Velocity

The highest speed and object will reach falling through the air

What is gravity

An attractive force between any two object that depend on the masses of the object

Eqaution for force

Force= Mass*Gravity--F+mg

Eqaution for weight

Weight=Mass*gravity- W+mg

Projectile Motion

Anything thrown or shot into the air

Does projectile Motion travel in a straight line

No

Horizontal and Vertical Motion

The force of throwing a ball

Centripetal Acceleration

acceleration toward the center of a curved or circular path

Momentum

A moving object is the product of its masa and velocity

Momentum Equation

Momentum= mass*Velocity

P+mv

Freefall and Weightlessness

Weight is a force

Mass is how much space something takes up

Energy

The ability to do work or cause change

What is energy measured in

Joules (J)

Examples of forms of energy

Kinetic

Thermal

Mechanical

Potential

Electric

Static

Radiant

Light energy travels at the speed of light

How fast is a light year

186,000 miles/per second

What is kinetic energy?

the energy a moving object has because of its motion

Equation of Kinetic Energy

Kinetic Energy=1/2 Mass*speed

When an object velocity _____ the kinetic Energy _____

Doubles; Quadrable

Examples: of Kinetic Energy

speeding bullet, flow of electric current, falling rock, flowing water

Potential energy

energy that is stored in an object due to its position or condition of an object.

What is a quick way to say potential energy

Stored energy

POtential

POsition

example of potential energy

Rock on a cliff has potential energy due to its position

Potential equation

P.E. = mgh

where m is the mass in kilograms, g is the acceleration due to gravity (9.8 m / s2 at the surface of the earth) and h is the height in meters

elastic potential energy

the energy of stretched or compressed objects

Chemical potential energy

the energy stored in the chemical bonds of a substance

gravitational potential energy

Energy stored by objects due to their position above Earth's surface.

Conversion of energy

Changes one from of energy to another

Mechanical Energy

Amount of KE and PE together