JANUARY 28, 2014
Announcements & Reminders
• To the teacher: Turn on the recording!
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• To students:
• Print the equation page before the test. Take both the page and your
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calculator with you. If you’re using your laptop, take your charger.
As for a WebAssign quiz, the only application you may have open is
WebAssign.
When you open the test, read the instructions first.
The first item is a check-off for your honesty pledge.
Submit items as you complete them. (You have 5 tries.)
If your school is cancelled for snow, email me on each day that you’re out
of school. When you return to classes, arrange with your proctor for an
alternate testing time. Send me the new information promptly.
If you don’t take the test Wednesday, get a head start on the assignments
for the rest of the week.
Something to check
Go to WebAssign and check the due time for E.19.01. Type
the due time in the chat window.
Typical Observations and Conclusions for L10B
a follow up while this lab is fresh in your mind.
Investigation V: When a finger is brought near the
grounded ball, the ball is attracted through polarization.
When the finger touches the ball, electrons are conducted
from the ball through the finger to ground, leaving the ball
with a net positive charge. The ball is then strongly
attracted to the negative balloon. When the ball touches the
balloon, electrons are conducted to the ball, leaving it with
a net, negative charge. The ball is then strongly repelled
from the balloon.
Typical Observations and Conclusions for L10B
Investigation VI: The Styrofoam is charged negatively by rubbing with
the fur. The pie plate is initially neutral, as evidenced by the fact that
both B and T test strips are attracted to the plate.
When the pie plate is placed on the Styrofoam, the pie plate is
polarized but is not charged. Styrofoam doesn’t give up electrons
readily. This is evidenced by the fact the the pie plate tests neutral after
being removed.
When the pie plate is placed on the Styrofoam and touched, electrons
are conducted through your finger to ground. The effect is so strong
that you may feel and see a spark. This leaves the pie plate with a net
positive charge, as evidenced by the fact that it repels the T tape.
Test coverage
• All assigned readings in Chs. 15 through 18
• All associated labs, assignments, and web content
• Emphases: Chs. 15 and 18
• See the AP review problem sets on fluids and
thermodynamics.
• Review the problem-solving guides. Know the sign
conventions for work and heat.
About doing AP-type problems
• On an AP test, you’re limited to 10-15 minutes per free
response problem. Thus, you need to work efficiently.
• Solve problems algebraically. Avoid calculation until the
last step of the problem or problem part. If you find you’re
doing a lot of calculation, then you’re not working
efficiently.
• As we examine the problems that students solved for
today, note which methods are most efficient.