Transcript Work and Energy

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HW check - Vocab 6
Test results
Standards
Video on Energy
Notes 6 Work and Energy
HW I due next time!
Movie
Lab next time…
Work and Energy
PAf.1:
Explain how the law of conservation of energy applies to the
transformation of various forms of energy (including mechanical energy,
electrical energy, chemical energy, light energy, sound energy, and thermal
energy).
PAf.2:
Explain the factors that determine potential and kinetic
energy and the transformation of one to the other.
PAf.3:
Explain work in terms of the relationship among the force
applied to an object, the displacement of the object, and the energy
transferred to the object.
PAf.4:
Use the formula W = Fd to solve problems related to work
done on an object.
PAa.1:
Generate hypotheses on the basis of credible, accurate, and
relevant sources of scientific information.
PAa.2:
Use appropriate laboratory apparatuses, technology, and
techniques safely and accurately when conducting a scientific investigation.
PAa.9:
Use appropriate safety procedures when conducting
investigations.
We must always change,
renew, rejuvenate
ourselves; otherwise we
harden.
Johan Wolfgang von Goethe
Fact: The average lifespan of a major league baseball: 7 pitches.
Work
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= force x distance
Work is only done if an object moves!
Measure in N*m, or the joule (J)
James Prescott Joule, 18181889
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English physicist and brewer, born in Salford,
Lancashire. Joule studied the nature of heat,
and discovered its relationship to mechanical
work. Wikipedia
Power
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Work/time
Work done per period of time, it is a rate of
how fast work is done
Measured in joules/second = watt
James Watt, 1736-1819
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Scottish inventor and mechanical engineer
whose improvements to the Newcomen steam
engine were fundamental to the changes
brought by the Industrial Revolution in both his
native Great Britain and the rest of the world.
Wikipedia
Potential energy
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Energy of position
PE = mgh
Usually work is done on an object to give it
potential energy
Can be mechanical or chemical
Kinetic energy
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The energy of motion
KE = ½ m*v2
= ½ times the mass of the object times the
speed squared
Energies are related
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Energy can be transformed from one form to
the other with work
Work-Energy Theorem
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Work = ΔKE
F * d = ½ m * v2
HW due next time:
Chapter HW: pp. 98-101
 I. Review questions2-20 even (due date:
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ISS tour 3
HW I check; Q & A
Energy Lab: due next!
E.S.B.
Today’s special
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ISS tour 4
Momentum Lab & Energy lab due (turn in now
on front desk)
Some notes
HW II due next
Energy graphic organizer
Rubber band cars planning (design & supplies)
Conservation of energy
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Energy cannot be created or destroyed; it may
be transformed from one form into another or
transferred from one object to another, but the
total amount of energy never changes
Simple machines
Efficiency
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Work done/energy used
Heat engines can never be 100% efficient
Sources of energy
Homework
Chapter HW: pp. 98-101
 II. Exercises 2-20 even; Problems 1-9 (due date:
__________)
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HW II check
Practice test
Rubber band car work time/supply check
Test & car race next time!
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Turn in Practice test on front desk
Test 6 Work and Energy
Enter answers in Smartresponse, turn in paper
test with sentences & essay/math problem
Work silently reading & doing vocabulary
(without talking) until ALL have finished testing
Race day!
Vocab 7 due next class!