*NAME*

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* **Transformations
of Energy Lab*

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*Use this paper to record your
data, but write conclusions, drawings, and graphs elsewhere!*

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*A ball dropped from a height of
1 meter bounces, and then loses energy as it hits. At the top at one meter, it
has its maximum gravitational potential energy, then the instant before it hits
it has its maximum kinetic energy, then it deforms as the front stops and the
back keeps going, giving it maximum elastic(spring) potential energy, then the
floor pushes back on it giving it kinetic energy until it returns to the top of
its bounce at gravitational potential energy again.*

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*Before you start:*

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*Draw a picture of the ball
bouncing once, labeling the types of energy. Also, use this diagram to indicate
places where the ball might lose energy ( it is transformed into something
other than a type of mechanical), and predict on the diagram the spot that you
think the ball will return to.*

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*A) Find the average height of a
normal ball bounce and use that to calculate its energy.*

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*take a normal ball. be sure to
mass it. Hold it at one meter. Let it drop. Avoid spinning the ball as you
release it or it will not drop straight. Measure the height of its bounce. Wait
at least 20 seconds. Repeat 9 times. Average the height.*

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*Beginning room temperature in
deg C:____________________ Starting
height _________ (in m)*

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*Ball Mass____________(in kg) Average
height (after 10)______ (in m)*

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*Use this to calculate the:*

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*Starting Gravitational
potential Energy_______________= mgh=GPE*

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*Maximum Kinetic
Energy______________ (= GPE start?)*

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*Speed at bottom
___________________ KE = ½ mv ^{2}*

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*Ending Gravitational Potential
Energy _____________=mgh*

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*Energy Lost __________________
in Joules*

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*Coefficient of Restitution
______________ (% height bounce)*

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*Conclusions: *

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*How did the results came out to
what you expected? How did the results show conservation or transformation of
energy? Draw a graph showing change in GPE and KE over time with your actual
results.*

*B) You predicted that the ball
would lose some energy due to heat. Find out how much in this part. *

*Have a cup of just enough water
(make sure to measure it!!) to cover the ball standing by, with a thermometer
or temperature probe already in it.*

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*Bounce the ball from 1 meter
again. This time do not wait at all in between bounces, catch it and quickly
drop it from one meter again. Do this at least 50-100 times quickly in a row.
the ball should feel slightly warmer.*

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*Note at least the first bounce
height, and the final bounce height. If they are different, mention in your
conclusions a possible explanation why.*

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*After bouncing the ball
rapidly, place it in the water and observe the temperature change. If the water
reaches a maximum, record this as the final temperature.*

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*Ball mass______ (in kg) *

* 1st
Bounce height______ (in m)
last bounce height_____ (in m)
# bounces______*

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* Water
Volume/Mass_______ (in
kg… 1L=1kg)*

*Starting Temp _____ in deg
C Final Temp ______ in deg C Change in Temp ______ in
deg C *

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*Calculate the amount of heat
energy the ball transferred to the water: (in
Calories) *

* Heat
= Q = MassWater * Change in T =______________*

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* in
Joules________ (Joules = Cal
* 4187)*

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*Divide by the number of bounces
to calculate the heat energy gained by the ball on each bounce.*

* ____________
Joules*

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*How does this compare to the
original calculation (from part A) of the energy lost on each bounce? Why are
they different?*

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*Conclusions: Why
might the bounce height start changing as you drop it fast? Why might the ball
get warmer? How does the heat energy gained on each bounce compare to Part A
calculation of the energy lost on each bounce and why they are similar or
different? Where might the rest of the energy have gone? How might the results
be inaccurate and what could have changed to make them better? Draw a graph
showing change in GPE and KE over time with your actual results. What are other
factors that could have affected your results?*

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*PART C)*

* Elastic Energy!*

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*Set up a light ball on a string
hanging off a ring stand. Make sure to find the mass of the ball and its
original gravitational potential energy.*

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*Set up an elastic or spring
that will hit the ball horizontally.*

*Measure the force it takes to
stretch/compress the elastic/spring and the distance from rest.*

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*Pull/push the elastic/spring
back and let it hit the ball. Measure the maximum height of the ball.*

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*Repeat your measurements at
least five times. *

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*Try different elastics or
balls.*

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*Calculate: the spring constant (k =
F/x), the starting elastic potential energy (1/2 k x ^{2}).*

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*If the EPE at the beginning
equals the KE when the ball was hit, what was the KE (=1/2mv ^{2}) ?*

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*What was the starting velocity?*

*What was the gravitational
potential energy at the end? (GPE =mgh)*

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*How much energy was lost?*

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* Where was it lost? How could you tell? Where might the rest
of the energy have gone? How might the results be inaccurate and what could
have changed to make them better? Draw a graph showing change in GPE, EPE, KE over time with your actual results.
What are other factors that could have affected your results? (include a
drawing!)*

*D) Pop its? Try placing the pop
it/or racquetball half on the floor and measure how far up it goes. Calculate
the gravitational potential energy at the top, its kinetic energy at the
bottom, and its speed at the bottom (using its mass). Try it several times and
see if the increased temperature each time makes a difference in the time it
takes to "pop", and the height it rises. Discuss your results and any
conclusions you might have. Draw a graph showing change in GPE and KE over time
with your actual results.*

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********* E for EXTRA!!!! (good
lab students will do at least one!) Repeat
any and all of parts A-D on a DIFFERENT FLOOR SURFACE (Carpet, paper, cloth,
etc.....) OR WITH A DIFFERENT OBJECT!! to see if it makes a difference and
discuss your results and conclusions!!*

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