Exam 2 Flashcards
1
Q
A rocket blasting into space is an example of Newton’s ___ Law.
A
Third.
1
Q
If you double the mass of an object, you essentially ____ the force.
A
Double
1
Q
If you double the distance of an object, you reduce its overall force by ____.
A
1/4
1
Q
A mirror ____ light.
A
Reflects.
2
Q
How does the force the Earth exerts on you compare with the force you exert on it?
A
Earth and you exert equal and opposite forces on each other.
3
Q
What is net force?
A
Overall force acting on an object which represents the combined effect of all individual forces put together.
4
Q
Over many days or weeks, a planet that moves westward relative to the stars, rather than the usual eastward relative to the stars, is experiencing what?
A
Apparent retrograde motion.
4
Q
Light passing through a window is an example of ____ light.
A
Transmission of
5
Q
Describe how Earth’s orbital speed changes throughout its orbit.
A
As Earth draws nearer to the sun it speeds up, slows down as it gets further away.
6
Q
Half of the major axis is called what?
A
Semimajor axis.
7
Q
Kepler’s second law.
A
“As a planet moves around its orbit, it sweeps out equal areas in equal times.”
7
Q
Galileo first recognized, Venus is __________.
A
Full whenever it is on the opposite side of the Sun from Earth, although we cannot see the full Venus because it is close to the Sun in the sky.
8
Q
Farthest point in orbit is called?
A
Aphelion.
8
Q
If you heat something until it turns red, is it hotter than if you heated it until it turns blue?
A
No, closer to blue means hotter.
8
Q
The distance between two wave peaks is?
A
Wavelength
9
Q
According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them _________.
A
Decreases by a factor of 9.
10
Q
Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be __________.
A
Geater than your normal weight at rest.
10
Q
Name Kepler’s 3 laws.
A
- Orbit of each planet around the sun is an ellipse with the sun at one focus (distance changes with orbit)
- As a planet orbits, it sweeps around in equal area in equal time (faster closer to sun, further is slower)
- More distant planets orbit at slower speeds (p2 = a3)
11
Q
A spaceship moving in space burning no fuel is an example of Newton’s ___ Law.
A
First.
12
Q
Force = Mass X Acceleration.
A
Newton’s second law.
13
Q
The great contribution of Nicholas Copernicus was to _________.
A
create a detailed model of our solar system with the Sun rather than Earth at the center.
13
Q
The great contribution of Tycho Brahe was to _________.
A
Observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion.
14
Q
What is a scientific model?
A
A conceptual representation created to explain and predict observed phenomena.
15
Q
What was the Ptolemaic model?
A
Earth-centered model of planetary motion published by Ptolemy.
15
Name Newton's three laws.
1. An object moves at a constant velocity if there is no net force acting upon it. (objects at rest, remain at rest)
2. Force = mass x acceleration
3. For any force, there is an equal and opposite reaction force.
16
A large planet and smaller planet both orbit a star. The larger planet has more mass and is closer than the smaller planet. Which planet orbits faster?
Even though the larger planet has more mass, it will orbit faster because it is closer.
17
Kepler's third law.
“More distant planets orbit the Sun at slower average speeds, obeying a precise mathematical relationship: p2 = a3”.
17
Energy carried by light.
Radiative energy.
17
The portion of the electromagnetic spectrum of light with the **greatest** energy has the \_\_\_\_frequency and the \_\_\_\_wavelenghts.
Higest. Shortest.
18
Light is a wave, not a particle.
False, light travels in wave but is made of photons.
19
What is pseudoscience?
Science with no observational evidence and not treating evidence in a truly scientific way.
19
An example of light absorption is \_\_\_\_.
Chalkboard absorbs all light
20
Who pioneered the Heliocentric model of the universe?
Copernicus. But he applied the old ideas of planets having perfectly circular orbits so his predictions were not much better. But he paved the way for Tycho, Kepler, and Galileo.
21
Let’s say that the gravitational pull between two stars
of equal mass (i.e., M1=M2) equals F. What is the force if
I double the mass of one star?
A) 5F
B) F
C) 2F
D) 4F
C) 2F
22
Wave speed is?
Wavelength X Frequency
24
Energy of motion.
Kinetic energy.
25
If you are standing on a scale in an elevator, what exactly does the scale measure?
The force you exert on the scale.
26
What is a true statement about simplicity and science?
Since we strive for a natural explanation, a theory that can more simply explain observations will tend to be more accepted.
26
Define speed.
How far an object will go in a certain amount of time.
27
Gamma ray photons have higher energies than
infrared photons. Which has the longer
wavelength?!
Infrared photons have the longer wavelength.
28
Not falsifiable.
Can not be proven false.
30
What is at the center of a geocentric model?
Earth.
31
Falsifiable.
Can be proven false.
32
Acceleration can be a change in speed or direction.
True.
33
The ___ were the first cosmologists.
Greeks.
34
Suppose you are in an elevator that is moving upward. As the elevator nears the floor at which you will get off, its speed slows down. During this time when the elevator is moving upward with decreasing speed, your weight will be \_\_\_\_\_\_\_\_\_\_.
Less than your normal weight at rest.
35
Arrange in order of Highest frequency to Lowest.
1. Infrared
2. X-Rays
3. Visible
4. Radio
5. Gamma
6. Microwave
7. Ultraviolet
1. Gamma
2. X-Rays
3. Ultraviolet
4. Visible
5. Infrared
6. Microwave
7. Radio
35
Stefan-Boltzman says that objects at ____ temperatures emit ____ light at ____ wavelenghts.
HIgher. More. All.
35
Who was the champion of the geocentric model of the universe? And what was its other name?
Greeks. Specifically Ptolemy. Also known as the Ptolemaic model. It stood for 1500 years and was built upon earlier versions of the geocentric model it put planets on smaller circles around the earth.
37
Theory is a guess.
False, theory makes predictions that survive repeated and varied testing.
38
Same as circling or turning momentum.
Angular momentum; any object moving along a curved path.
39
Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon?
Its wavelength and energy.
40
What goes up, must come down is one of Newton's laws of motion.
False.
40
No question. Just reminder to study Pages 21-32, as well as 47 in tutorial book.
41
Who made the breakthrough that planets must have elliptical orbits?
Kepler.
43
What is at the center of a heliocentric model?
The sun.
45
~500 BC this person was the first to teach that the Earth was round.
Pythagoras.
47
Gravity does not affect a feather and a brick dropped from a building the same way.
False.
48
What is free-falling?
When you fall and there's nothing to prevent you from falling.
49
Does a planet with a circular orbit around a star speed up at any point during its orbit?
No. Same distance = same speed.
50
Describe what p and a mean in p2=a3.
“p” is the planet’s orbital period in years, and “a” is its average distance from the Sun (semi-major axis) in astronomical units.
51
\_\_\_ is emitting light.
Emission.
52
What is an ellipse's eccentricity?
Describes how much an ellipse is stretched out.
53
A planet's distance from the sun will remain the same during its orbit.
False.
55
The long axis of the ellipse is called its _____ axis.
Major.
57
Consider two stars (X and Y). If Star X is 3 parsecs away, and Star Y is 5 parsecs away, which has the greater parallax angle?
Star Y.
58
Why is a rose red?
A. The rose absorbs red light.
B. The rose transmits red light.
C. The rose emits red light.
D. The rose reflects red light.
D. The rose reflects red light
60
On the moon, my weight is \_\_\_, my mass is the \_\_\_.
Less. Same.
61
Conservation of energy.
Energy cannot appear out of nowhere or disappear into nothingness.
62
What would happen to a planet’s orbital speed if it’s mass were doubled but it stayed at the same orbital distance?
It would orbit with the same speed.
64
The average of the perihelion and aphelion distances is called
The semi-major axis.
65
Newton's third law.
For any force, there is always an equal and opposite reaction force.
67
What is an object's momentum?
Product of an object's mass and velocity.
68
Gravity follows an inverse square law with distance, which means the force of gravity between Earth and a spaceship ____ as the spaceship gets farther from Earth.
Weakens.
68
How would the strength of the force between the moon and earth change if the mass of the moon was doubled?
The strength of the force of the moon would double.
70
When would you expect to see Venus high in the sky at midnight?
Never.
71
A pitcher throwing a ball is an example of Newton's ____ Law.
Second.
73
Your ___ is the force that a scale measures when you stand on it.
Weight.
74
Potential energy.
Stored energy.
75
What were Galileo's two main contributions?
Moons of Jupiter. Phases of Venus.
76
A circle is an ellipse with an eccentricity of?
Zero
77
The ideas put forth by Copernicus led to the ____ revolution.
Copernican.
79
Closer to the sun means ___ orbital periods than further away which means ___ orbital periods.
Shorter. Longer.
81
The greater the eccentricity of an ellipse, the more ____ it is.
Elongated.
82
Which forms of light are lower in energy and frequency than the light that our eyes can see?
Infrared and radio.
83
Newton's first law of motion.
An object in motion moves at constant velocity if there is no net force acting upon it.
85
Why is Newton's version of Kepler's third law so useful to astronomers?
It can be used to determine the masses of many distant objects.
86
Two stars at the same temperature, one large and one small, will appear the same brightness.
False, the larger star will appear brighter.
87
Kepler thought the force responsible for the pull of planets was what?
Magnetism
89
The first person to make a model of the universe was?
Thales in ~600 BC.
90
Planets move ____ when close to the Sun, and ____ when farther from the Sun
Faster. Slower.
91
A circle is not an ellipse.
False, it is.
92
Imagine that Venus is in its full phase today. If we could see it, at what time would the full Venus be highest in the sky?
At noon.
93
The ___ the object’s temperature, the ____ the wavelength of
the peak for the light emitted by the object.
Higher. Shorter.
94
The Moon has a ____ acceleration than Earth, because it has a _____ mass
Larger. Smaller.
95
Mass of a planet directly affects its orbital period.
False. Orbital period is independent of the mass of the orbiting object.
95
Gravity follows an inverse square law with distance, which means the force of gravity between the Moon and a spaceship ____ as the spaceship approaches the Moon.
Increases.
96
Shorter average wavelength is emitted by?
Hotter objects.
97
If a car is making a gradual turn, it is experiencing a ___ force.
Net.
98
Your are not truly weightless in space.
True, you're in a free-fall.
99
A _______ is a graph of an
object’s energy output versus wavelength.
Blackbody curve.
100
If a spaceship is exactly between the earth and mars, would the pull of one planet be greater than the other? why?
Yes, greater from earth because it is more massive. it would have to travel further away from earth and closer to Mars to feel a strong pull from Mars.
101
The amount of matter in your body is your?
Mass.
103
Frequency is?
The number of times per second a wave vibrates up and down.
104
Let’s say that the gravitational pull between two stars
of equal mass (i.e., M1=M2) equals F. What is the force if
I double the distance between the stars?
A) 0.25F
B) F
C) 2F
D) 0.5F
A) 0.25
105
Which of the following waves travel fastest? Gamma, Ultraviolet, X-Rays, or Radio?
They all travel at the speed of light.
106
“The orbit of each planet around the Sun is an ellipse with the Sun at one focus”.
Kepler's first law.
108
Speed and direction.
Velocity.
109
What do we mean by a geocentric model of the universe?
A model designed to explain what we see in the sky while having Earth located in the center of the universe.
110
Two bodies attract each other with a force that is directly proportional the product of their masses and is inversely proportional to the square of the distance between them - is an example of?
Newton’s law of gravitation states.
111
The greater the mass of an object, the ___ it's gravitational force.
Stronger.
112
\_\_\_\_ is the absence of color, ____ is all colors combined.
Black. White.
113
Perihelion
Closest to the sun during orbit.
114
The ___ a wavelength is, the ____ its frequency (energy)
Longer wavelength, lower frequency. Shorter wavelength, higher frequency.
