Physics... THE FINAL (PART ONE)

What are the equations used to calculate velocity and distance for a freely falling object?

v=gt d=1/2gt squared (If you did NOT get this, you are IN TROUBLE. This has been stated at least three times in various ways.)

What is the equation for the speed/velocity of an object in free fall?

velocity=9.8 m/s/s*elapsed time v=gt

The mass of one object decreases by half and the force is

divided by 2

What is the instantaneous speed of an object that is at its highest point when it is thrown straight up in the air?

0 m/s (acceleration is stillllllll 9.8 m/s/s)

At the end of time (t), an object in free fall has fallen a distance equal to

1/2gt squared

Inverse square of 9

1/81

An approximate value of the acceleration of an object in free fall

10 m/s/s

What is the terminal velocity of a person without a parachute? How will it change with a parachute?

150-200 km/h (just go with 150 because that's what Ms. J used on the quiz). With the parachute it is about 15-20 km/h (again, go with 15).

Direction of the acceleration in free fall

Down

Direction of the force in free fall

Down

What is the definition of free fall?

Free fall is when an object is falling with only the force of gravity acting on it.

The weakest of the four fundemental forces

Gravity

How does weight affect terminal velocity?

Larger weight=higher terminal velocity

Einstein's theory involving the speed of light

Special Relativity

Fundemental force that binds together protons

Stong Nuclear

Theory of the universe that vibrating strands of energy are the most fundemental units in nature

String Theory

What two factors determine the amount of air resistance?

The speed at which the object is traveling and the surface area of the object.

Define elapsed time

The time that has passed

Why are there no large objects in the solar system today with very low tangential velocities?

They long ago crashed into the sun.

How many Academy Awards did Apollo 13 win and what were they? What year was this movie made and who directed it?

2: -Best flim editting -Sound 1995 directed by Ron Howard (If you got this right I am proud of you...I dub thee queen of useless trivia.)

An accurate value of acceleration of an object in free fall

9.8 m/s/s

What factors will cause the terminal velocity to be faster (higher speed)?

Less surface area More mass and weight

What is tangential velocity?

Sideways velocity that ensures circular motion instead of collision.

True or false. The weight of a rock at Earth's center is zero.

True

Physics theory of atoms that involves the probability of behavior of subatomic particles

Quantum Mechanics

Explain why a dropped coin reaches the ground before a feather

Air resistance slows the movements of things with large surface areas, such as a feather.

True or false. Weightlessness is the absence of gravity.

false

Newton realized that the moon must falling _____ the earth.

Around

How can you cause a mass to have more than one terminal velocity?

By changing the mass or surface area. Sometimes the change of mass is not significant enough to be significant :).

Einstein wanted to combine this force with Gravity

Electromagnetism

What is the Copernican theory?

Heliocentrism...the solar system is heliocentric (centered around the sun)

The English physicist ______________ first measured G.

Henry Cavendish

WOW. You're done. Congratulations!!! Now read it again :D I apologize if ________________________________________.

I offended anyone with my snarky comments throughout the flashcards. It made it MUCH more interesting for me and I hope it did for you, too.

WARNING: SOME OF THE FIRST 20-ISH CARDS HAVE A TON OF INFO ON THEM, BUT IT GETS MUCH MORE SIMPLE :) What does it mean to say that Newton discovered that Gravity is Universal?

Newton did not discover gravity. Newton discovered that gravity is universal. Everything pulls on everything else in the universe in a way that involves only mass and distance.

Can the unit of time be negative?

No, it is always positive, but all the other factors are, or can be, negative in free fall.

How many Earth radii are you from the center of Earth if you are standing on its surface?

One (6.38*10 to the sixth power)m

Describe the acceleration of an object that is thrown up in the air with a specific starting velocity. Include the time interval that takes the object fromt the starting point and the objects return to the same point.

The acceleration is always the same. ALWAYS!!! 9.8 m/s/s or 10 m/s/s if approximating. The time it takes to return to the same point is equal for the time that it takes to rise.

It's ten and I'm tired...(Ooooo, alliteration!) Define physics. FYI this will most likely NOT be on the test. In other words, please don't memorize it.

The branch of science concerned with the nature and properties of matter and energy. The subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.

What is the action-reaction force pair that explains the motion of rockets? Which law is this?

The exhuast gases push on the rocket and the rocket pushes on the exhaust gases. Newton's Third Law.

Fundemental force responsible for radioactivity

Weak Nuclear

What is Weak Nuclear and what is its function?

Weak Nuclear is a subatomic force and allows neutrons to turn into protons (responsible for radioactivity). EXPLOSIONS.

What forces are in balance when an object reaches its terminal speed?

Weight and air resistance

Explain what would happen if a coin and a feather were dropped in a vacuum tube.

Without the presence of air resistance, both would have the same acceleration and hit the ground at the same time.

If you have made it this far without cheating or giving up and taking a break...______!!!

YAY

A 10 kg brick and a 1 kg book are droped in a vacuum. The force of gravity on the 10 kg brick is a. 10 times greater than the force on the 1 kg book b. zero c. the same force as on the 1 kg book

a

A ball is thrown straight up. At the top of the path its instantaneous speed is a. 0m/s b. about 5m/s c. about 20m/s d. about 10m/s

a

An object has a constant mass. A constant force on the object produces a constant a. acceleration b. velocity c. both a and b d. none of the above

a

If air resistance is negligible, a falling object can be considered

freely falling or in free fall

Used to represent acceleration due to gravity

g

Letter used to represent acceleration due to gravity

g (little g NOT big G because big G is the Universal Gravitational Constant)

What is the equation for universal gravitation?

F=G(m1m2/d squared)

True or false. The force of gravity is the strongest of the presently known four fundemental forces.

FALSE

Is the following sentence true or false? In real life, air resistance has no effect on the acceleration of a falling object.

False

True or False. Newton believed that the mass of the moon affects how it falls.

False

True or False. Newton discovered gravity.

False

Consider water drops leaking from a water faucet. As they fall they a. remain at a relatively fixed distance from each other b. get farther apart c. get closer together

b

When an object is thrown straight up into the air, what is its acceleration when it is moving upward?

9.8 m/s/s

What is the acceleration of the same object in the above question when it is descending?

9.8 m/s/s You should be getting this by now :)

Accelertion cause by the force in free fall

9.8 m/s/s or 10 m/s/s

What is a vacuum?

A vacuum is a space in which only gravity could act on an object. It can be used in free fall circumstances.

How are gravitational field lines related to the acceleration of an object around Earth?

Any mass near Earth will be accelerated in the direction of the field lines at that location.

What is the equation for Universal Gravitation to calculate the force of gravity between any two masses given the mass of the two objects and the distances between them?

F=Gm1m2/r squared F is directly proportional to mass one and mass two and inversely proportional to the square of the distance between the centers of the two masses.

What did Henry Cavendish do?

G was first measured 150 years after Newton's discovery of universal gravition by an English physicist, Henry Cavendish. Cavendish accomplished this by measuring the tiny force between lead masses with an extremely sensitive torsion balance. A simpler method was later developed by Phillipp von Jolly, who attatched a shperical flask of mercury to one arm of a sensitive balance. After the balance was put in euqilibrium, a 6-ton lead sphere was rolled beneath the mercury flask. The flask was pulled slightly downward. In effect, the gravitational force. F between the lead mass and the mercury was equal to the weight that had to be placed on the opposite end of the balance to restore euilibrium. Since the quantities F, m1, m2, and d were all known, the value G could be calculated.

Einstein's theory of gravity

General Relativity

Force acting on an object in free fall

Gravity

What did Einstein figure out about Gravity? What is the name of his gravitational theory? Refer to the "Magic Box".

He discovered that gravity is the curvature of spacetime and how it is directly related to the energy and momentum of whatever matter and radiation are present. It can be described as a geometric property of space and time. General Relativity. He based it off Special Relativity, which deals with the speed of light. Magic Box: deals with gravity and BIG things. It is ODERLY and PREDICTABLE. Einstein.

Suppose a particle is accelerated through space by a constant 10 N force. Suddenly the particle encounters a second force of 10 N in a direction opposite to that of the first force. The particle a. is brought to a rapid halt b. theoretically accelerates to speeds approaching the speed of light (HAHA..suuuurrre) c. continues at the speed it had when it encountered the second force. d. gradually decelerates to a halt. e. none of the above

IT IS C!!! :) If you don't believe me, ask Ms. J or check your quiz corrections. It is c because the second force causes it to have a net force of zero and therefore continues at a constant velocity.

What is the effect of mass on the acceleration of free fall?

If it is in free fall, there is no air resistance. If there is no air resistance, mass does not have an effect on the accleration and it is ALWAYS 9.8 m/s/s even at the top when the velocity is 0 m/s.

What is the inverse square law and why is it significant?

If one quantity is multiplied by a factor, another quantity decreases by the square of the factor. The inverse square of 9 is 1/81.

Newton understood the concept of ______, developed by Galileo, that without an outside force, moving objects continue to move at constant speed in a straight line.

Inertia

What limitation or assumptions come with these formulas? (Or when can these be used? Certain circumstances must be met.)

Initial Velocity is 0 m/s unless the initial velocity is given. Velocity continuously increases downward. Accelerates ALWAYS 9.8 m/s/s Directions of force, velocity, and acceleration is downward.

Describe the velocity of an object that is thrown up in the air with a specific starting velocity. Include the time interval that takes the object from the starting point and the objects return to the same point.

It decreases by 9.8 or about 10 each second from the specific starting velocity while traveling upward. It takes the same amount of time to go up as it does to come back down.

What is the Universal Gravitational Constant? What is its value? When does its value change?

It describes the strength of gravity. The value of G tells us that the force of gravity is a very weak force. It is the weakest of the presently known four fundemental forces. (The other three are the electromagnetic force and two kinds of nuclear forces.) We sense gravitation only when masses like that of Earth are involved. The force of attraction between you and a classmate is too weak to notice (but it's there!). The force of attraction between you and Earth, however, is easy to notice. It is your weight. 6.67*10 to the negative eleventh power The value NEVER CHANGES

What is gravity?

It is a constant DDoooWWnnnward force. It is always present. AAAALLLLWWWAAAYYYYSSS. Also, it is the only force that acts on an object in free fall.

What is air resistance?

It is a form of friction with the air. It has all the qualities of friction.

What is the direction of the air resistance?

It is opposite the motion. It has the SAME qualities as FRICTION.

What is Quantum Mechanics? Who discovered it? Refer to "Magic Box".

It is physics at a subatomic level. It's a game of chance. There is an idea that all 100 chances of a certain type of probability will happen, just not necessarily in our universe-but in a parallel one. In a parallel universe, it would be possible to pass one solid object through a solid barrier. This theory of probability has never been contradicted in experiement. Magic Box: Contradicted Einstein's theory of General Relativity. Deals with atoms and small things. It is PrObaBILItY aND uNpReDictable. Subatomic forces and particles: Strong Nuclear and Weak Nuclear.

Define terminal speed/velocity

It is the speed/velocity at which the acceleration of a falling object is zero because weight and air resistance are balanced. (IF YOU WERE READING THIS, YOU WOULD HAVE NOTICED THAT THE ACCELERATION IS ACTUALLY ZEROOOOO AT TERMINAL VELOCITY!!!!!!!)

What is a "burn" and what does it do?

It is turning on the rocket engine. This would produce a force, which would produce a change in velocity/acceleration. This means that the astronauts needed or wanted to changed their speed or direction so that they could adjust their path.

What is terminal velocity?

It is when the acceleration is 0 because the friction and weight forces have been balanced. You can reach two terminal velocities by changing the mass or surface area.

What is a force/gravitational field?

It occupies the space surrounding a massive body. A gravitational field is an example of a force field, for any mass in the field space experiences a force.

What would happen to the motion of a planet if its tangential velocity were reduced to zero?

It would crash into the sun.

Where is Earth's gravitational field zero?

Its center

State the Law of Universal Gravitation.

Newton's law of universal gravitation states that every object attracts every other object with a force. For any two objects, this force is directly proportional to the mass of each object. The greater the masses, the greater the force of attraction between them. Newton also deduced that this force decreases as the square of the distance between the centers of the objects increases. The farther away the objects are from each other, the less the force of attraction between them.

A 1kg river rock and a 10 kg small boulder are dropped from the back of a truck at the same time. Identify which rock will strike the ground first.

Same time

What is Strong Nuclear and what is its function?

Strong Nuclear is a subatomic force and holds neutrons and protons together.

The mass on one object doubles and the force is

multiplied by 2

Identiy the conditions needed for a feather and coin to fall at the same rate.

They will fall at the same rate in a vacuum.

True or false. The gravitational influence of every object is exerted through all space.

True TRUE TTRRUUEE

Is the following sentence true or false? For each second of free fall an object falls a greater distance than it did int he previous second.

True

True or False. At the top of a mountain, your weight is slightly less than at ground level.

True

True or False. Circular motion is accelerated motion, which requires a force.

True

True or False. Newton's theory of gravity confirmed the Copernican theory of the solar system.

True

True or false. The moon falls beneath the straight line it would follow if no force acted on it.

True

Consider the gravitational force between Earth and a meteor in outer space. If the meter moves so its distance from the Earth's ceneter doubles, the ravitational force on the meteor will be_. a. one quarter b. half c. double d. quadruple e. eight times greater

a

Newton reasoned that the gravitational attraction between Earth and the moon must be _. a. reduced by distance b. independent of distance c. directly proportional to distance d. the same at all distances e. all of the above

a

The distance between the objects' centers of mass decreases by half and the force is

multiplied by 4

Two objects move toward each other because of gravitational attraction. As the objects get closer and closer, the force between them A. remains constant B. decreases C. increases

c

Which statements are true about freely falling objects? a. they all fall with the same acceleration b. the net force acting on them is their weight c. their weight-to-mass ratios are always the same d. their acceleration is g, the acceleration due to gravity

a b c AND d (ALL OF THEM)

the word for the rate at which velocity changes

acceleration

If you thought Apollo 13 was a amazing movie and decided to watch it again less than two weeks later, you _____. (There are two possibilities).

are easily influenced by teachers who wish to enfore their infatuations on you (or) just liked the movie because of your opinions

Aunt Minnie throws a rock downward, and air resistance is negligible. Compared to a rock that is dropped, the acceleration of the rock after it is thrown is a. less b. the same c. more

b

Suppose an object is in free fall. Each second the object falls a. the same distance as in the second before. b. a larger distance than in the second before c. with the same instantaneous speed d. with the same average speed e. none of the above

b

The terminal speed for a person parachuting (with the chute open) is about a. 0km/h b. 15km/h c. 150km.h d. 1500km/h

b (The parachute was OPEN)

Which of these affects the amount of air resistance experienced by an object? a. time in contact w/air b. speed of object through air c. surface area of object d. weight of object

b and c

Why are people often unaware that gravity accelerates us?

because we are almost always in contact with Earth

The pulls that Earth and the moon exert on each other is action at a distance because the bodies interact without

being in contact

A 20N falling object encounters 4N of air resistance. The magnitude of the net force on the object is a. 0N b. 4N c. 16N d. 20N

c

A freely falling object starts from rest. After falling six seconds, it will have a speed of about a. 6m/s b. 30m/s c. 60m/s d. 300m/s

c

Newton had the insight to see that the a. mooon is moving b. moon orbits Earth c. force on the moon has the same nature as the force on an apple d. moon always keeps one side toward the Earth e. none of the above

c

The gravitational force betwen two massive spheres a. is always an attraction b. depends on how massive they are c. both a and b

c

What word best describes the direction of tangential velocity? a. up b. down c. sideways d. backwards

c

The terminal speed for a person (without a parachute) is about a. 0km/h b. 15km/h c. 150km/h d. 1500km/h

c (hmmm...if you did the last problem I should hope that you did not choose b...and the answer was also in a previous question).

Describe the distance traveled each second of an object that is thrown up in the air with a specific starting velocity. Include the time interval that takes the object from the starting point and the objects return to the same point.

d=1/2g(t squared) The distance decreases each second on the way up and increases each second on the way down. Once again, the time it takes to travel up is equal to the time is takes to travel back down.

the equation for distance

d=1/2gt squared

The word for how far an object has fallen

distance

What is the equation for the distance of an object in free fall?

distance=(1/2)9.8 m/s/s*(time squared) d=1/2g(t squared)

The distance between the objects' centers of mass doubles and the force is

divided by 4

An object dropped in the air that experiences no air resistance is said to be in

free fall

An object moving under the influence of the gravitational force only is said to be in

free fall

Earth's gravitational field interacts with objects by causing them to experience

gravitational forces

When an object is in free fall, the only force acting on the object is

gravity Yes. IT. IS. GRAVITY. only gravity

Effect of air resistance on free fall

slows things down

The word for how fast something freely falls from rest after an elapsed time

speed

Field lines show the _______ and ________ of a force field.

strength direction

Field lines are closest together where a field is

strongest

Rather than define your weight as the force of gravity that acts on you, it is more practical to define weight as

the force you exert on the floor

The constant G in this equation is called the _________________ and describes the ______________.

universal gravitational constant strength of gravity

Used for both speed and velocity in the equation for instantaneous speed

v v for velocityyyyyyy

The equation for speed and velocity

v=gt

Pressure against Earth is the sensation we interpret as

weight