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Physics Pre-Comps
These are the flashcards for everything we did in Physics this year so far
149
Physics
6th Grade
12/22/2010

Additional Physics Flashcards

 


 

Cards

Term
What is the Scientific Method?
Definition

1. Recognize a problem or something unknown

2. Make a hypothosis

3. Make predictions about your hypothosis

4. Perform expirements to test your hypothosis

5. form a conclusion

6. relay your data

Term
What is a scientific hypothosis?
Definition
an educated guess that must be tested by expirements
Term
When is a hypothosis proven through expirements?
Definition
Never
Term
How many expirements can prove you wrong?
Definition
One
Term
What is science?
Definition
The study of the universe
Term
What si a Quantative measurement?
Definition

a measurement that produces a definite, specific value:

 

Ex: Classes at BASIS are normally 50 minutes long

Term
What is a Qualitative Measurment?
Definition

a measurement that is a non-numerical (no numbers) discription 

 

Ex: Classes at BASIS are just the right length

Term
The Metric System. What are the common units?
Definition

Length -meters

Mass -grams 

Weight -Newtons

Time -seconds 

Volume -liter or cubic cenitmeter

Temperature -Degrees Celcius

Term

What are the Metric System prefixes and abbreviations? 

 

Hint: You should have 12 of the prefixes and 12 of the abbreviations

Definition

Trillion - Tera

Billion - Giga

Million - Mega

Thousand - Kilo

Hundred - Hecto

Ten - Deca

 

Tenth - deci

Hundredth -centi

Thousandth - milli

Millionth - micro

Billionth - nano

Trillionth -pico

 

Abbreviations are just the letter that the prefix starts with except for micro   -u (sort of a cursive u)


Term
What is Accuracy?
Definition
the state of correctness
Term
What is Presion?
Definition
how specific your answer is, whether it is wrong or right
Term
What is the Margin of Error?
Definition
the amount of acceptable error in an expirement
Term
What is a referance point?
Definition
an object that is staying in place compared to another object to detect movement
Term
Whne is an object in motion?
Definition
when it changes position over time when compared to a referance point
Term
What is position?
Definition
the point or area occupied by a physical object
Term
What is speed?
Definition
a measurement of how fast something is moving
Term
What is the equation for speed?
Definition
Speed= distance/time
Term
What are some units of speed?
Definition

miles/hour

meters/second

etc.

Term
What is constant speed?
Definition
When an objects average speed and instantaneous speed are the same
Term
What is the equation for average speed?
Definition
Average Speed= total distance/total time
Term
What is instantaneous speed?
Definition
an objects speed at any one moment in time
Term
What are the equations for distance and time?
Definition

Distance= speed x time

 

Time= distance/speed

Term
What is Velocity?
Definition

the speed and direction of an object

 

Term
What is constant velocity?
Definition
constant speed with no change in direction
Term
What is the equation for average velocity?
Definition
average velocity= total distance/ total time
Term
Velocities can be combined to create what?
Definition
resultant velocity
Term
How do you find the resultant velocity of two velocities in the same direction?
Definition
add the velocities together
Term
How do you find the resultant velocity of two velocities in opposite directions?
Definition
subract the smaller velocity from the larger one
Term
What is acceleration?
Definition
the rate at which an object's velocity changes
Term
What does it mean to accelerate?
Definition
To change velocity
Term
Is acceleration how much velocity changes?
Definition
No, it is how fast it changes
Term
What is the equation for acceleration?
Definition
Acceleration= change in velocity/time interval
Term
What is another equation for acceleration?
Definition

Acceleration=final velocity - initial velocity

                         ---------------------------------

                time interval

Term
What is the acceleration in which velocity increases called?
Definition
positive acceleration
Term
What is acceleration in which velocity decreases called?
Definition
negative acceleration or deceleration
Term
What are the units of Acceleration?
Definition
m/s2
Term
What is inertia?
Definition
the tendancy of objects to resist a change in motion
Term
State Newton's First Law of Motion.
Definition
"An object at rest remains at rest and an object in motion remains in motion at a constant velocity unless acted upon by an unbalaced force."
Term
What is mass?
Definition
Mass is the quantity of matter in an object
Term
What else is mass?
Definition
the measure of an objects inertia
Term
What is weight?
Definition
the force upon an object caused by gravity
Term
Are weight and mass the same thing?
Definition
NO!!!!!!!!!!!
Term
Mass and weight are directly porportional. This means what?
Definition
That if you double an objects mass, you also double its weight. If you halve an objects mass, you also halve the objects weight
Term
When does mass change?
Definition

Never!!!!!!

 

*This is for inanimate objects*

Term
Does inertia ever change? How do you know?
Definition
No, because if mass never changes and it follows an objects inertia, then inertia never changes either
Term
Would it be easier to push a car on the moon or on earth?
Definition
It would be the same
Term
Would it be easier to lift a car on the moon or on earth?
Definition
on the moon because there is less gravity
Term
What is volume?
Definition
the size of an object
Term
Why are mass and volume not nessisarily porportional?
Definition
Because of density
Term
State Newton's Second Law of Motion.
Definition
"The acceleration of an object is directly porportional to the net force acting on that object, is in the direction of the net force and is inversely proportional to the mass of the object."
Term
What is the equation for acceleration and how is it directly and inversely proportional?
Definition

Acceleration=force/mass

 

If force is doubled, acceleration is doubled.

If mass is doubled, then acceleration is halved.

Therefore, Force and acceleration are directly proportional and mass and acceleration are inveresly proportional.

Term
What is a force?
Definition
Simply, a push or a pull.
Term
What is net force?
Definition
it is the sum of the forces acting on an object
Term
How do you find net force?
Definition
Add the forces acting in the same direction and subtract forces acting in opposite dirrections.
Term
What is a vector quantity?
Definition
A force that involves both magnitude and dictection.
Term
What is a scalar quantity?
Definition
Something that involves just magnitude.
Term
What produces acceleration?
Definition
The net force.
Term
What is the unit of force?
Definition
A Newton
Term
When is an object in equilibrium?
Definition
When it is acted upon by balanced forces
Term
What is a balanced force?
Definition
When the sum of forces acting on an object equals zero.
Term
How can a balanced force be created?
Definition
Two forces must be equal in magnitude and opposiite in direction.
Term
What happens when two or more forces added together do not equal zero?
Definition
It is an unbalanced force and acceleration will occur.
Term
If an object's net force is zero, is it in equilibrium?
Definition
Yes
Term
Can an object that is moving be in equilibrium?
Definition
Yes, if it is moving at a constant velocity.
Term
What is static equilibrium?
Definition

When an object is at rest and not accelerating is in equilibrium.

 

 

Term
What is dynamic equilibrium?
Definition

When an object is in motion and is not accelerating.

 

In other words, an object that is moving at a constant velocity.

Term
What kind of equilibrium is a glass on a table in? Why?
Definition

Static Equilibrium

 

Because its velocity is 0 m/s and isn't accelerating, therefore the net force on the glass is zero.

Term

 

Learn the equilibrium table.

Definition
Or else.
Term
What is a normal force?
Definition
A force produced by a surface an object is resting on, created by the atoms in the surface.
Term
What is tension force?
Definition
A force produced by a push or pull.
Term
What is friction? What is it caused by?
Definition

a force that occurs when objects slide over each other

 

caused by atoms clinging together at many points of contact

Term
What does the magnitude of friction force depend on?
Definition

the object's weight and the material of the object's

 

Surface area does not make a difference

Term
What is the direction of friction force?
Definition
opposite the direction of motion
Term
When does friction occur?
Definition
Once a horizontal force is exerted
Term
Which has more inertia, a jug filled with air or a jug filled with water? Why?
Definition
The jug filled with water because it has more mass
Term
State Newton's Third Law of Motion.
Definition
" Whenever one object exerts a force on a second object the second object exerts an equal and opposite force on the first."
Term
Does it matter which object is the action force or reaction force in Newton's Third Law of Motion?
Definition
No, it can be either.
Term
What does Newton's Third Law of Motion mean?
Definition
That forces are equal in strength and opposite in direction.
Term
When do forces occur?
Definition
simultaneously
Term
Can an action force exsist without a reaction force?
Definition
No.
Term
Forces always act in ________ .
Definition
pairs
Term
Do action and reaction forces act on the same object?
Definition
No.
Term
What would happen if action forces and reaction forces acted on the same object?
Definition
They would cancel each other out and acceleration wouldn't be possible.
Term
What is the equation for momentum?
Definition
Momentum=mass x velocity
Term
Does an object at rest have momentum?
Definition
No, only moving objects have momentum.
Term
What is the equation for momentum when direction isn't important?
Definition
Momentum=mass x speed
Term
A moving object can have a _________ amount of momentum if mass is __________ and velocity is ________ especially if both are __________.
Definition

large

large

large

large

Term
If there is a large amount of momentum in an object, is it easy to stop its motion?
Definition
No.
Term
Are momentum and inertia the same thing? Why?
Definition
No, because Inertia depends on mass only and momentum depends on both the mass and velocity. Furthermore, inertia is involved with both moving and stationary objects while momentum only is involved with moving  objects.
Term
When does momentum change?
Definition
WHen an object's mass, velocity, or both change.
Term
What is required to change momentum?
Definition
an unbalanced force
Term
What is an impulse?
Definition
How much force is being exerted over a certain period of time.
Term
What is the equation for impulse?
Definition
Impulse=force x time
Term
How do you increase an object's momentum as much as possible?
Definition
Exert a large amount of force over a long period of time.
Term

Why does it hurt less when you run into a haystack then when you run into a wall?

 

 

Definition
In both cases your  momentum is decreased by the same amount, which means that the impulse needed to stop you is the same. The time of impact is greater for the haystack so the force of impact is greater for the brick wall then the haystack.
Term
The ________ must be exerted by something _______ to the object.
Definition

impulse

external

Term
If no force is external to the system of objects, what happens to momentum?
Definition
It does not change
Term
Is momentum a vector quantity or a scalar quantity?
Definition
Vector
Term
Momentum is always ______ in a collision.
Definition
conserved
Term
What is the net momentum of coliding objects after the collision?
Definition

It is equal to the net momentum before the collision.

 

Net momentum before = Net momentum after

Term
What is an elastic collision?
Definition
a collision where no deformation or heat generation occurs.
Term
What is an inelastic collision?
Definition
involves deformation and/or heat generation
Term
What makes up everything in the universe?
Definition
matter and energy
Term
What is matter?
Definition

Anything that has mass and volume.

 

His definition: substance

Term
What is energy?
Definition
The movment of matter.
Term
What is the equation for work?
Definition
Work = force x time
Term
When calculating work, does the path matter?
Definition

No, the path taken does not matter only the final distance matters.

 

Example - If you picked up a rock in the back yard and carried it to the front yard then took it back and put it in the exact place you first picked it up, you have done ZERO work. 

Term
If you lift an object 6 feet off the ground, you've done twice as much work as lifting that object 3 feet off the ground. Why?
Definition
Because the distance has doubled.
Term
If you are holding a 500 Newton barbell over your head, how much work are you doing, why?
Definition
You are doing NO WORK because the distance is zero.
Term
What are the units for work?
Definition
Joules
Term
What is power?
Definition
a measure of how fast work is done
Term
WHat is the equation for power?
Definition
Power = Work done/time interval
Term
Twice the power means that the same amount of work can be done in _______ the time, or twice the ___________ can be done in the same amount of time.
Definition

half

work

Term
What is the unit for power?
Definition

joule/second

 

- or -

 

Watts

Term
How many Watts are in 1 Horsepower?
Definition
746 Watts
Term
What is the unit for energy?
Definition
joules
Term
What two types of energy are mechanical energy?
Definition
kinetic energy and potential energy
Term
What is potential energy?
Definition
Energy that is stored by an object relative to another object
Term
What is gravitational potential energy?
Definition
The potential energy of an object due to an elevated position
Term
The amount of gravitational potential energy possessed by an object is equal to what?
Definition
the work done against gravity in lifting it
Term
What is the equation for Potential energy and why?
Definition

Work = force x distance

Force = mass x acceleration

The distance is obviosly the height and acceleration means the acceleration of gravity 

SO if you plug in the equation for force  into the equation for work.. you get

 

Potential Energy = mass x gravity x height

Term
What is kinetic energy?
Definition
The energy of motion
Term
What is the equation for Kinetic Energy?
Definition
Kinetic Energy = 1/2 of the mass X velocity2
Term
If velocity is doubled, what happens to the kinetic energy?
Definition
It is quadrupled
Term
What is the Work-Energy Thereom?
Definition

States that

 

Work = the change in Kinetic Energy

Term
What is the Law of Conservation of Energy?
Definition
"Energy can not be created or destroyed; it may be transferred from one form to another, but the total amount of energy never changes."
Term
What are machines?
Definition
devices for multiplying or changing the direction of forces
Term
Why is a lever useful?
Definition
because you can apply a small force over a large distance to create a large force over a small distance
Term
What is the equation for efficiency?
Definition

Efficiency =

useful energy output / total energy input

Term
What is a wave?
Definition
any disturbance that transmitts energy through matter or space
Term
When a wave travels, does it take the material through which it traveled with it?
Definition

No.

For example, sound waves often travel through air, but the air does not travel with the sound.

Term
As a wave travels, what does its energy do work on?
Definition
Everything in its path.
Term
What is a medium?
Definition
a substance though which a wave can travel, and can be a solid, liquid, or gas
Term
What is a vibration?
Definition
The back and forth movement of a particle
Term
How can waves travel?
Definition
particles vibrate and pass energy to the particles next to them and those particles vibrate and pass energy to particles next to them , and so on and so forth.
Term
What is a mechanical wave?
Definition
A wave that requires a medium to travel
Term
What are some examples of a mechanical wave?
Definition
sound waves and waves in an ocean or lake
Term
What is an electromagnetic wave?
Definition
A wave that requires no medium to travel.
Term
What are some examples of electromagnetic waves?
Definition
visible light, microwaves, radio waves, and X rays
Term
What is a transverse wave?
Definition
A wave where the particles vibrate up and down perpendicular to the direction the wave is traveling
Term
What is the highest point of a wave?
Definition
Crests
Term
What are the lowest points of waves called?
Definition
troughes
Term
What are longitudinal waves?
Definition
waves where the particles vibrate back and forth along the path that the waves travel
Term
What is a compression?
Definition
A section where the particles become crowded together in waves
Term
What is a rarefaction?
Definition
A section where the particles are spread out in a wave
Term
What is amplitude?
Definition

the maximum distance a wave vibrates from its rest position 

the larger the amplitude the "taller" the wave and the more energy it carries

Term
What is wavelength?
Definition

the distance between any two adjacent crests or compressions in a series of waves 

also the distance between any two adjacent troughs or rarefactions 

Term
What is frequency?
Definition
the number of waves produced in a given amount of time
Term
What is period?
Definition
the time it takes a wave to complete one back-and-forth oscillation
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