Class Project
Physics 1010-042
Summer 2013
The Project Parts
Part 1: Star Identification:
Mimosa
 353 light years from the earth
 The light we see now left the star in
approx. 1660
 Has 8 solar radiuses compared to the
suns 1
 Solar luminosity is 34,000 compared to the suns 1
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Beta Centauri
350 light years away for the earth
Left in approx. 1663
Mass of 8 solar masses compared
to the suns 1
Solar luminosity 41,700 greater
than the sun.
Alpha Centauri

4.367 light years away
 The light that we now see left the star approx
March of 2009
 The star is about 10% bigger than our sun.
 Alpha Centauri- has a solar luminosity of 1.519
compared to the sun’s solar luminosity which
is 1.

Gamma Crux
 88.6 light years away from
earth
 Light we see now approx. 1924
 Has a 84 solar radiuses
compared to the suns 1
 Has a solar luminosity of 1,500
compared to the suns 1
Coal sack
Delta Crucis
 Located 345 light years away from the earth
 Light we see now left in approx. 1668
 Size is 8 solar radiuses compared to the suns
1
 10,00 solar luminosities compared to the
suns 1
Above: photo of the Centaurus/Crux (Southern Cross) sector of the milky way.
Australian flag with the Southern Cross on the
Centaurus/Southern Cross
right and Beta Centauri in the lower left
star chart with Alpha and
Beta Centauri on the left
Part 2: Equation Analysis:
These equations are in your textbook so that should be a good source of accurate
information about them.
Equation 1: E = mc2
Answer or do the following:
Question 1: Find out what the things in this equation (using your book or a net search
will do it) are and identify them as either variables or constants.
E= Energy (variable)
M= Mass (variable)
c2=speed of light (constant)
Question 2: What is the size of c2?
c2 = 8.98755179 × 1016 m2 / s2
Question 3: Are mass and energy related? Answer yes or no and then provide a brief
explanation of your answer based on the analysis of the equation.
Yes, mass and energy are synonymous but to convert then back and forth you
need the equation E = mc2 which proves that basically the proportionality of mass
to energy is equal to the speed of light squared.
Question 4: Analyze the statement: “if it is possible to change mass into energy a little
bit of mass could produce a lot of energy”. Is it true or not? Provide a brief explanation
based on your analysis of the equation
No. mass and energy cannot be created or destroyed. Mass in all forms has
energy, and energy in all forms has mass. Neither one can exist without the other
existing also. In the equation mass remains mass and contains energy. neither the
amount of mass nor the amount of energy changes, since both are properties which are
connected to each other via a simple constant. If mass were to leave the system it would
take a proportion of energy with it and vice versa.
Equation 2: d = gt2/2
…where:
d = distance an object falls when released from rest (no air resistance)
g = acceleration of gravity at the Earth’s surface
t = time the object has been falling
Question 5. Which of the following statements do you agree with and why? Use the
equation to support your answer (you can also refer to the learning from equations
module files).
a) heavy objects fall faster than lighter objects
- Disagree. Weight plays no part in the equation as long there is no air
resistance. The only considerations are distance falling, acceleration of gravity,
and time that the object has been falling.
b) objects fall at the same speed (if no air resistance) and weight doesn’t matter.
-True. Weight does not stipulate how fast an object falls as long as there is
no air resistance. The only considerations for how fast an object will fall is
distance, acceleration of gravity, and time.
Equation 3: v = gt
…where:
v = velocity of a falling object if released from rest (no air resistance)
g = acceleration of gravity at Earth’s surface
t = time the object has been falling
Question 6: Which of the following statements do you agree with and why? Use the
equation to support your answer (you can also refer to the learning from equations
module files).
c) heavy objects fall faster than lighter objects
-false. Weight is not a consideration of this equations. The only
consideration that stipulate the velocity of a falling object( without air resistance)
are time and acceleration
d) objects fall at the same speed (if no air resistance) and weight doesn’t matter.
-True. Objects will fall at the same rate(if no air resistance)
Now go online and view this link. If the link is inoperable go to google video and do a
search on “Galileo hammer feather experiment”.
http://www.youtube.com/watch?v=4mTsrRZEMwA
Question 7: For most of recorded history, people thought that heavy objects naturally
and under all conditions fall faster than lighter objects. Why did it take us so long to
realize the true state of affairs?
People did not understand, or believe a vacuum to even be possible., measuring
devices for acceleration were unavailable and theories of air resistance were not
understood, and thus the theories of Aristotle were accepted. Galileo, although
unable to prove that objects fall at the same rate in a vacuum because he lacked a
vacuum, was able to show, by dropping object of different weights off the tower
of Pisa that a 10lb object would not fall 10X faster that a 1lb object. Such as was
taught by the principles of Aristotle.
Question 8: The Earth’s gravity DOES exert a greater force on heavier objects than
lighter ones (these forces are called weight). However, with no air resistance objects fall
at the same speed in a given gravity field. The weight difference can be thousands of
pounds to one and the objects still fall at the same speed. What physical property of
mass compensates for the difference in applied forces?
I think that acceleration is the physical property that compensates for the
difference. Acceleration of an object depends not only on the force(weight) but
on the objects resistance to motion or its inertia.
Equation 4: e = 1 – Tcold/Thot
…where:
e = efficiency of energy use
Tcold = the temperature of the environment surrounding the heat engine
Thot = the internal operating temperature of the engine
This is the equation for the efficiency of a heat engine (your car is a heat engine unless
you have an electric model). An e = 1 is 100% efficiency, meaning 100% of the energy
gets used to do what you want to do with no “wasted”, unrecoverable energy. An e = 0
is an efficiency of zero with none of the energy going to what you want to do and all of
the energy being “wasted” or in unrecoverable forms.
The temperatures in this equation are in the Kelvin scale where the lowest temperature
is 0 degrees. There are no negative temperatures in the Kelvin scale. A temperature we
might encounter on Earth would be about 300 degrees Kelvin.
Question 9: Is it possible to achieve 100% efficiency, in theory, by lowering the
temperature of the environment surrounding the heat engine (Tcold)? Why or why not?
In theory yes. If you were able to lower the temperature of the environment
surrounding the heat engine (Tcold) to absolute zero.
Question 10: Is it possible, in practice, to achieve 100% efficiency by lowering the
temperature of the environment surrounding the heat engine (Tcold)? Why or why not?
It is not possible, because you cannot reach absolute zero.
Question 11: Is it possible to achieve 100% efficiency, in theory, by raising the internal
operating temperature of the heat engine (Thot)? Why or why not?
According to the formula you could reach 100% efficiency if you were to have an
infinitely high temperature.
Question 12: Is it possible to achieve 100% efficiency, in practice, by raising the
internal operating temperature of the heat engine (T hot)? Why or why not?
No, because you cannot raise the temperature of a heat engine infinitely high.
Question 13: If your car is not electric, it is a heat engine and is subject to the efficiency
equation. Is it possible to build a car, using any kind of burning fuel, that is 100%
efficient? Explain.
No it is not possible. Whenever there is any type of movement, or combustion
there is energy that is lost.
Part 3: Learning about a Law of Physics
Pick any Law or Principle of Physics in your textbook and:
1. Give me an explanation of what it is and what it means.
Second law of Thermodynamics
States that the net entropy of the universe is continually expanding. In other
words, we will never see a shattered glass cup jump off the ground, reform, and
land on the table a whole cup again. Things go from order to disorder.
2. Give me 3 examples in the real world involving the law or principle.
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Heat never naturally flows from a cold object to a colder one.
Molecules of a perfume bottle, when opened, will go from the ordered state
of being in the perfume bottle to being more disorderly in the environment.
Glass cups will fall off a table and shatter, but will never jump off the
ground, reform, and land on the table whole again.
Part 4: Explanation of Fermi’s Paradox and possible resolution
This involves the possible existence of alien life in the Universe. A net search should
bring up some immediate information on the subject.
1. Clearly explain what this paradox involves and why it is a paradox.
This paradox is about statistics. In a galaxy of trillions and trillions of
stars, there are many different planets like ours that could develop life. Many of
these planets are heated by suns that are much older than our own. As a result
very advanced civilizations should have cropped up and begun colonizing the
galaxy. If this is probable, where are they, why has there not been any type of
incontrovertible evidence of extraterrestrial, intelligent life?
2. List and briefly explain (like in a paragraph for each) 4 possible resolutions (reasons
we haven’t apparently had contact with any aliens) to the paradox.
1. If these civilizations are so advanced that they are colonizing the galaxy,
what would they stand to gain from reaching out to us? When was the last
time you tried to communicate with an ant? Maybe they are so far
advanced that they are simply not interested in us at our present state.
2. Maybe they have become so far advanced that their view on ethics and
morality so far supersede our own that they see us as such a barbaric
people that they prefer to just leave us alone to fend for ourselves.
3. Perhaps because of our relative cosmic innocence, we are viewed as a type
of interstellar nature reserve. When the pilgrims landed they brought many
different types of disease with them. Maybe aliens are not visiting us
simply because their impact on us would be detrimental to our society.
4. Maybe they are visiting us, but still choose to remain hidden. Maybe they
are visiting us to just study our behavior, but still want us to be able to fend
for ourselves.