Monday, September 10, 2001
Announcements:
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Exam 1 is two weeks from today.
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Last year's exam and available equations will be posted on-line later this
week.
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Practice problems on the Harcourt website are available.
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Remember to work through example problems in your book before doing homework
problems.
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When using WebAssign, only the last submission is graded; no penalty for
multiple submissions.
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Answers to essay (text box) questions on WebAssign are visible after assignment
is due.
Review of HW2b:
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P.2.18 (ball bouncing off wall): a = (vf - vo)/dt watch
signs!
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Acceleration is opposite direction of initial velocity, and therefore negative
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P.2.47 (Ranger/deer problem): t = D/vo + vo/2a
Chapter 3: Motion in Two Dimensions
Same physics as 1D motion. Simply treat each component
independently and add vectors.
Review of vectors and components:
Vectors A and B have the same magnitude and orientation.
Does A = B?
Vector A is 10 m long and oriented 30 degrees from the positive x axis.
(T/F): A = Ax + Ay
A = Axx + Ayy
A = Acos30x + Asin30x
A = Asin60x + Acos60x
The top of a tree is 30 degrees above horizontal when viewed from a distance
of 50 feet from its base. How tall is this tree?
A) 20 ft. B) 30 ft.
C) 40 ft. D) 50 ft. E)
60 ft.
Assumptions for Projectile Motion (p.60)
ConcepTests
Demos:
Simultaneous ball drop
Minute Paper: One thing you learned today, one question
or confusion you have.
Assignments:
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RWP3 - Bank Robbery (due Friday)
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HW3b (due Friday) Ch.3: P 9, 21, 27, 39, 41