Transcript Chapter 6 Work and Energy

Chapter 6
Work and Energy
Objectives: The student will be
able to:
Perform several investigations in order to make
conclusions about the conservation of energy.
Inquiry for Conservation of Energy
Part I
• Observation of a spring loaded cart on an
incline and make note of the cart’s motion
once the spring is released.
Inquiry for Conservation of Energy
Part I
• If the cart were to be “shot” up a steeper
vs. a shallower ramp, describe how its
motion will change.
• Write down your prediction in your
notebook. Be sure to justify your
predictions.
• Think-pair-share.
• Class Discussion
Inquiry for Conservation of Energy
Part I
• You will now design an experiment with the cart and the
ramp to investigate how the angle of a ramp affects the
motion of the cart. Once it is discussed, perform and
collect data from your experiment.
• Materials
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Dynamics cart with spring bumper or plunger
Ramp
Meter stick
Protractor
Stop watch
Masses
Books for incline
Large white boards
Inquiry for Conservation of Energy
Part I
• Your group will present using the whiteboards your
design and findings.
Objectives: The student will be
able to:
Perform several investigations in order to make
conclusions about the conservation of energy.
Inquiry for Conservation of Energy
Part I
• Based on your findings, what conclusion can we make
about the angle of the ramp and the motion of the cart?
• If height was not the same, how could this be explained?
• Should multiple measurements have been made for
each angle?
• How many?
• Was one angle change sufficient or do you think multiple
angle changes should have been made?
• If there was a lot of friction, how would your results
change?
Inquiry for Conservation of Energy
Part II
• Energy exists in the following:
• Compression of the spring (spring
potential energy SPE)
• Movement of the cart (kinetic energy KE)
• Earth-cart system (gravitational potential
energy GPE)
Inquiry for Conservation of Energy
Part II
Are these statements consistent with what you found in Part I?
Inquiry for Conservation of Energy
Part II
• Observation of a spring loaded cart on an
incline and make note of the cart’s motion
once the spring is released.
• The SPE can be changed by compressing
the spring different amounts.
Inquiry for Conservation of Energy
Part II
• You are to design an experiment to
investigate how the energy (SPE) stored in
the spring depends on the distance by
which it is compressed. Specifically, if you
increase the compression by a factor of 2,
what happens to the SPE?
• See next slide for specifics.
Inquiry for Conservation of Energy
Part II
• Part II (A): Qualitative Investigation of Potential Energy
• Design an experiment to qualitatively describe the relationship
between compression of the spring and the gravitational
potential energy. Be prepared to present a convincing
argument and defend their results. You will create a
presentation using the large whiteboards to be shared with the
whole class.
• Part II (B): Quantitative Investigation of Potential Energy
• Design an experiment where you will collect data in order to
quantitatively support their claim. You will complete your
experiment and share your results with the class.
• Procedure should be done on the whiteboard and graphs done
using Excel with trend line and equation on graph. Think of
how to get a linear relationship.
Inquiry for Conservation of Energy
Part II
• Potential Errors
– What role does friction play in the experiment? How can you minimize or
take into account the frictional effects?
– If the spring could only be compressed by two values (or if the spring
could be compressed for multiple values), how would your experiment
change?
– How does the amount of compression of the plunger change the manner
in which you measure the distance the cart moved and/or the maximum
height?
Evaluation
• Individually, you will make a claim about
each investigation with supporting
evidence, and then explain how the
conservation of energy can be applied to
these investigations.
• This will be due Monday.
Homework
Conclusions
• Based on the investigations, what do you
think is meant by conservation of energy?