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Class Project
Physics 1010-400 and 401
Fall 2016 Signature Assignment and Semester Project
Every general education class at SLCC, including physics 1010, requires a signature
assignment (special assignment) and a reflective writing essay about the signature
assignment to be posted on the student’s ePortfolio web page.
The signature assignment for Physics 1010-400 and Physics 1010-401 for Fall 2016
consists of several parts, each of which must be done:
1) Star Identification
16 points
2) Equation Analysis
26 points
3) Learning about a Law of Physics
12 points
4) Explanation of The Rare Earth Hypothesis
and some of its features
16 points
70 points total
The Reflective Writing essay is about your signature assignment. It should be
presented as a coherent whole (an essay not just a list of answers to questions). It,
along with your project, should be put on an ePortfolio page. When you send me the
URL of that page of your ePortfolio I will go online and grade your reflective writing and
project presentation.
This is worth an additional 30 points.
There is more information about how to set up an ePortfolio page and what the
reflective writing essay should include at the end of this document and in the syllabus.
As far as length, your reflective writing essay should be a couple of pages of well
organized text at the minimum. Structure this essay so it is coherent and makes sense
as a whole; don’t just list a series of questions and answers.
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The Signature Assignment Parts
Part 1: Star Identification:
The photo below is of the Lyra region of the milky way.
Pick 4 of the stars in the photograph below. Label each of these stars on the photo.
Then tell me the following things about each star:
1) Its name
2) Distance from Earth in light years (a light year is how far light can travel through the
vacuum of space moving at 670 million miles per hour for a year. By everyday
standards a light year is an enormous distance)
3) When the light from the star now visible in the skies of Earth actually left the star (if a
star is 10 light years away its light now visible in the skies of Earth left that star 10 years
ago in 2002)
4) Its size compared to the Sun (you can do the comparison using the star’s radius to
the Sun’s radius or the star’s volume to the Sun’s volume)
5) The star’s luminosity compared to the Sun (luminosity is a measure of brightness)
A good way to proceed is to use the star chart (also attached) to identify the stars by
their greek letters or proper name and then do a net search on the names to find
information.
On final page
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Vega
Beta lyrae
Epsilon lyrae
Gamma Lyrae
Above: photo of the Constellation Lyra
A suggested line of approach to this part of the project is to use the star chart that
follows to identify the stars in the photo and then find the information you need using net
searches on the internet.
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Star chart of the constellation Lyra (bigger start size on chart means brighter as it
appears to us in our sky)
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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 of object (variable) C = Speed of light in a
vacuum (Constant 3×108 m/s)
Question 2: What is the size of c2?
C2 is the speed of light in a vacuum squared = 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 related, the more mass you have the greater the
energy and vice-versa. If you double the mass of an object it will have more energy
within it.
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. It doesn’t have to be super complex and you
don’t need to “solve” the equation; just use the equation in a straightforward way (for
help, consult me or the tutorial files in the ‘learning from equations” module in canvas.
It is true that a lot of energy can come from a very small mass, with the speed of
light squared being a constant you could have different outputs based on the mass. For
example the force of an atom has a lot of energy, while not accessible all the time, this
small amount of mass has high energy.
The equation E = mc2 comes from the relativistic energy/momentum equation in Albert
Einstein’s Special Theory of Relativity (the book has a chapter on that theory). The full
relativistic energy/momentum equation is:
E2 = p2c2 + m2c4
…where the new variable p is the relativistic momentum (momentum at very high
speed). If an object is not moving its momentum is zero and the equation reduces to:
E2 = m2c4
If we want the energy E instead of the energy squared we can take the square root of
this equation to get:
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E = mc2
Since this involves an object that is not moving this energy is sometimes called the rest
energy or energy of existence of an object.
Now this equation is technically not complete because when you take a square root you
get positive and negative solutions so it should really look like this:
E = mc2
This is a curious result as we will see from the following series of questions. Your book
on the chapter on Special Relativity may be of some help here and the internet definitely
will be useful.
The equation:
E = mc2
can actually be split into:
E = mc2
and:
E = -mc2
It’s this second equation we want to look at now, especially that negative sign. There is
something rather odd going on here. Let’s try to find out what it is!
Question 5. Is the mass m ever negative?
Mass can be negative, in theory. It is unproven if mass can be negative. All we
are aware of is mass that is positive.
Question 6. Is c ever negative (hint: remember that c is a velocity and as such has a
magnitude and a direction. Positive and negative can be used to designate direction)?
Yes C can be negative, when an object is moving away it will have this effect.
Question 7. Can c2 ever be negative?
No, anything squared will end up positive. -22 is always 4, as for any other
negative that will be put in.
Question 8. Given your previous answers, can mc2 ever be negative?
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If mass is negative which if ever proven then yes it can be, otherwise the answer
is no. All mass we are aware of is positive and c2 will always come out as a positive
input.
We could multiply the equation by -1 and get:
E = mc2
Question 9. Is energy ever actually negative (can something have a negative energy of
existence)?
Energy can be negative depending on what we are talking about, potential or
Kinetic, but in the equation the answer is no.
Question 10. Does energy ever have a direction (is it scalar or vector)?
Energy is scalar, not a vector. Energy does not have a direction of travel and can
be measured at precise point.
Question 11. Can the negative on the left hand side of the equation ever mean a
direction for energy?
No, energy is scalar there for it will be positive with what is inputed.
Question 12. Some scientists thought that this negative sign was just a mathematical
oddity or scrap that had no physical meaning. Why might they think that? (use your
previous answers)
They might think it can be negative, which it can, but it hasn’t been found yet. For E to
be negative we would have to have a negative mass first, which has yet to be
discovered but is in theory possible.
Question 13. Is the negative sign actually meaningless or does this mathematical
peculiarity actually mean something? If so, what?
Mathematical peculiarity has meaning to that it has an output that can’t be proven
yet. If they disregard the negative sign then they throw away the possibility without it
ever being proved wrong or right.
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Part 3: Learning about a Law of Physics
Pick any Law or Principle of Physics in your textbook and:
1. List its name and give me an explanation of what it is and what it means.
Newtons first law of physics(law of inertia), an object at rest will stay at rest unless acted
on by another force. An object will stay still unless something/someone exerts a
force/push upon it.
2. Give me 3 examples in the real world involving the law or principle.
1. a ball sitting on a flat surface stays still, a ball on a slope has gravity acting on
it so it will move down the slope.
2. If you kick a ball in space it will continue to go that direction and speed
because there is no friction or opposing force to slow it down. Unless it encounters
anything.
3. If you are driving in a car at a high rate of speed and come into contact with a
stationary object, such as a wall, you will come to a stop. If the wall has more mass that
is and won’t move. Your body will not just stop but slam forward because it wanted to
keep going in the direction. The rear end wants to keep going the same speed as the
front makes contact and smashes the car.
Part 4: The Rare Earth Hypothesis and its Features
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 and briefly explain the Rare Earth Hypothesis
The Rare Earth Hypothesis states that it there is small to if not no other intelligent
life in the universe. States that we have existed for such a small time with just the right
conditions that we if there was other intellectual life that they are probably gone by now,
and that the chances of having a planet like ours form is so rare that it is unlikely.
2. List and briefly explain 3 important features of the Rare Earth Hypothesis (features
are ideas, concepts or facts that support the hypothesis)
1. The small inhabitable zone that is around a star is hard for planets to be found
in and is rare to see them in this location
2. Another idea is that the solar system must consist of planets like ours, small
rocky planets near the star and large gas giants on the outer rim.
3. Having a consistent orbit at all times is another idea in this hypothesis, if the
planet is near a gas giant or any other large mass object it can throw the planet out of
the inhabitable zone.
3. Planets around other stars have been discovered in significant numbers (exoplanets).
What light has this shed on the hypothesis? Explain briefly.
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Planets that have been found rarely have water in a liquid state which we know is
required for life on a planet. With it being so rare to having liquid water on a planet it
shows that the odds are even less likely.
Star Identification
Our suns Lumosity = 3.75×1028 = 1L (L is Lumosity unit)
Star name: Vega Distance: 25.05 Light years Light left in 1991. 1.41 times bigger than our sun.
Stars brightness: 50L
Star name: Epilson Lyrae Distance: 162 Light years Light left in 1854. Star brightness: 18L Size:
dual star, radius NA
Star Name: Beta Lyrae Distance: 960 Light years. Light left in 1056AD. 15.2 times bigger than
our sun. Star brightness: 6,500L
Star Name: Gamma Lyrae Distance: 620 Light years. Light left in 1396AD. 15 times bigger than
our sun. Star brightness: 2100L
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