Transcript Document 7531989

CSUN PHYSICS WORKSHOP
SUMMER 2001
July 9 - July 20
Instructors:
Dr. Julio Blanco
Dr. Say-Peng Lim
Supported by the California PostSecondary Education Commission
DIAGNOSTIC TEST
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RELAX! The test is ANONYMOUS.
Please answer the questions as best you can.
You have 1 hour.
Do not write on the question-sheets.
You should keep a duplicate copy of your
answers for your own diagnostic.
PRELIMINARIES
• Explanation of diagnostic test.
• Register for course credit - grades based on
workshop participation/final exam.
• Introduction and background of participants
- classes taught, calculus?
• HyperNews & homepage introduction.
• Various software for self-learning.
• Textbooks - Active Physics?.
PRELIMINARY SUMMER PROGRAM
Date
Topics
Content Standards
July 9,10
One-dimensional motion
Newton's First and Second Laws
Vectors
Experiment - Force Table
Newton's Third Law
Static Equilibrium
Circular Motion
Gravitation
Experiment - Free Fall
Work and Energy
Linear Momentum
Experiment - Ballistic Pendulum
Temperature and Kinetic Theory
Heat
Thermodynamics - 1st & 2nd Laws
Experiment - Work & Heat
Heat Engines
Entropy and 2nd Law
Experiment - Heat Engine
1-a
1-b, 1-c
1-i, 1-j
July 11,12
July 13,16
July 17,18
July 19,20
1-d
1-h, 1-k
1-g, 1-l
1-e, 1-f, 1-m, 5-o
2-a to 2-c, 2-h
2-d, to 2-h
3-c
3-a
3-d
3-b, 3-g
3-e, 3-f
Why Study Physics?
• It is extremely interesting.
• It is the most fundamental of all the
sciences.
• It forces you to think through a problem and
develop problem solving skills.
• Learn analytical and modeling skills.
• The ability and faith that you can solve
any/complex problems.
• Prepares you well for lifelong learning.
What Students Should Learn
• NOT Laws of Physics!
• Skills Physicists use in applying these Laws
- transferable to other fields.
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Simplification
Idealization
Approximation
Pictorial, Graphical, and Mathematical
Representations of phenomena
– Mathematical/Conceptual Modeling
STYLE OF WORKSHOP
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Reading Quizzes at the beginning of each topic.
Each topic is divided into several key concepts.
Introduction of Concept.
Test of concept: question posed
individual answer
group discussion
revised answer/tally
Explanation
Reading Quiz - Kinematics
1. The slope of the curve in the position
vs.
time graph for a particle’s
motion gives
___ 1. the particle’s speed.
___ 2. the particle’s acceleration.
___ 3. the particle’s average velocity.
___ 4. the particle’s instantaneous
velocity.
___ 5. not covered in the reading
2. Is it possible for an object’s
instantaneous velocity and instantaneous
acceleration to be of opposite sign at
some instant of time?
___ 1. yes
___ 2. no
___ 3. need more information
3. Without air resistance, an object
dropped from a plane flying at constant
speed in a straight line will
___ 1. quickly lag behind the plane.
___ 2. remain vertically under the plane.
___ 3. move ahead of the plane.
___ 4. not covered in the reading
assignment
4. A ball is thrown downward (not dropped)
from the top of a tower. After being
released, its downward acceleration will
be
___ 1. greater than g.
___ 2. exactly g.
___ 3. smaller than g.
___ 4. not covered in the reading
assignment
Kinematics: One-dimension
• Importance of a Reference frame - origin
and direction; Cartesian, Polar.
• Distance versus Displacement.
• Speed versus Velocity.
• Average speed:
v  x
t
• Instantaneous speed: limit as t 0
• Graphical representation.
Quantitative Problems
1) An airplane travels 2100 km at a speed of
800 km/h, and then encounters a tailwind
that boosts its speed to 1000 km/h for the
next 1800 km. What was the total time for
the trip? What was the average speed?
2) Calculate the average speed and average
velocity of a complete round-trip in which
the outgoing 200 km is covered at 90 km/h,
followed by a one-hour lunch break, and the
return 200 km is covered at 50 km/h.
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Velocity - rate of change of displacement.
Acceleration - rate of change of velocity.
Average acceleration: a  v
t
Instantaneous acceleration: limit as t  0
Graphical Representation.
Constant acceleration motion.
v  vo  at
x  xo  vot  1 at 2
2
v2  vo2  2a(x  xo)
• Why? Easy; acceleration due to gravity
g  9.8 m/s2
Quantitative Problems
1) Determine the stopping distance for an
automobile with an initial speed of 25 m/s
and human reaction time of 1.0 s for an
acceleration of -4.0 m/s2
2) A car moving at 5 m/s undergoes an
acceleration of 3 m/s2 to a final speed of
20 m/s. What was the time taken? Through
what distance did the car move during the
third second?
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Vector Quantities
• Vectors are quantities that have magnitudes
and directions; and add like displacement.
• Addition and Subtraction of Vectors.
• Multiplication of Vectors?
• Resolving a Vector into components Trigonometry and the Pythagorean theorem
Quantitative Problems
1) Vector A is 8.08 units long and points along
the negative x-axis. Vector B is 4.51 units
long and points at 45 degrees above the
positive x-axis. What is the sum of the two?
2) A skier is accelerating down a 30 degree hill
at 3.8 meters per second squared. What is the
vertical component of her acceleration? If she
starts from rest and accelerates uniformly,
how long does it take her to reach the bottom
of the hill if the elevation change is 335 m?
Projectile Motion
• Refers to the two-dimensional motion under
the influence of gravity only.
• Key - resolve motion into independent
horizontal and vertical motions; time being
the quantity that is common.
• Trajectory that results is a parabola; Range;
Maximum height.
Quantitative Problems
A rescue plane wants to drop supplies to
isolated mountain climbers on a rocky ridge
245 m below. If the plane is traveling
horizontally with a speed of 70 m/s, how far
in advance of the recipients (horizontal
distance) must the goods be dropped?
If the goods were released 425 m in advance
of the climbers,what vertical velocity (up or
down) should the supplies be given?