Transcript Lecture powerpoint

PHY 2048C
General Physics I with lab
Spring 2011
CRNs 11154, 11161 & 11165
Dr. Derrick Boucher
Assoc. Prof. of Physics
Outline for Lecture 1
•Syllabus
•Course Resources tour
•LON-CAPA tour
•Standard Lecture Format
•PRS clickers
•Chapter 1
•Chapter 2
Course Resources
Dr. Boucher’s website
http://ruby.fgcu.edu/courses/dboucher/
Syllabus
http://ruby.fgcu.edu/courses/dboucher/p2048%20syllab
us%20s11%20boucher.pdf
Schedules
http://ruby.fgcu.edu/courses/dboucher/Spring_2011_G
Pschedule.pdf
Course Resources, cont.
Lab Resources
Schedule:
http://ruby.fgcu.edu/courses/dboucher/lab_schedule_s
pring_2011.htm
Procedures, other helpful files:
http://ruby.fgcu.edu/courses/dboucher/lab%20resource
s.htm
Course Resources, cont.
Equation sheet (still being prepared)
•All the equations you’ll need for the course
•Conversion factors and constants
•Provided for every exam
•Useful for study
So, what do you need to know?
•Mensuration formulas (areas, volumes, etc.)
•Geometry, trig and calculus
•Metric prefixes giga, mega, kilo, centi, milli, micro,
nano
LON-CAPA
Our online homework system
Free to use
Locally administered (problems get solved!)
Allows discussion among students, instructor
Take a look:
http://orion.cas.fgcu.edu/adm/roles
Standard Lecture Format
1.
2.
3.
4.
5.
6.
7.
8.
Announcements, glimpse at schedules
Handouts
PRS clicker logins (attendance)
Old business (handing graded items back,
reviewing homework, etc.)
(Maybe) quiz on past material and/or current
reading
New concepts and equations (kicking the tires)
Example Problem(s)
Repeat 6 & 7 as necessary…
Chapter 1 and 2
Practice Problems
Chap 1: 1, 3, 7, 13, 15, 19, 23, 25, 27, 29, 37, 41
Chap 2: 3, 7, 9, 11, 31, 57, 63, 69, 71
Unless otherwise indicated, all practice
material is from the “Exercises and Problems”
section at the end of the chapter. (Not
“Questions.”)
Chapter 1
•READ IT
•Review and learn as necessary
•Some highlights follow
The Particle Model
•For simple motion we can consider the object as if it
were just a single point, without size or shape.
•All the mass is concentrated at that point.
•A particle has no size, no shape, and no distinction
between top and bottom or between front and back.
Making a Motion Diagram
Simplify a “movie” in one diagram
tree
Equally spaced points
represents constant
speed; the car travels
equal distances in equal
times
Position at equal time intervals
EXAMPLE 1.1 Headfirst into the snow
Average Speed, Average Velocity
To quantify an object’s fastness or slowness, we define
a ratio as follows:
Average speed does not include information about direction of
motion. Average velocity does include direction. The average
velocity of an object during a time interval Δt, in which the object
undergoes a displacement Δr, is the vector
In one dimension, direction is either + or – (it’s up to you which
real direction + or – actually means). Then, r is x or y.
Instantaneous Velocity
Average velocity is calculated over an extended period
of time.
As ∆t gets smaller and smaller, we can think of the velocity at a
particular instant in time. This is especially useful when velocity
changes.
Graphically, v is the slope of a line tangent to the position vs. time
curve. You may (should) recognize this as the derivative!

 ds
v
dt
Notation in text: “s” means x, y or z…whatever direction you are dealing with
Example problem
Chapter 2 #6 (p. 65)
PRS
Clicker
Questions
Sample question;
Dr. Boucher’s favorite color is,
A. Blue
B. Green
C. Chartreuse
D. Red
E. None. Dr. Boucher sees in black-and-white.
At the turning point of an object,
A. the instantaneous velocity is zero.
B. the acceleration is zero.
C. both A and B are true.
D. neither A nor B is true.
E. This topic was not covered in this chapter.
REDO (after discussion)
At the turning point of an object,
A. the instantaneous velocity is zero.
B. the acceleration is zero.
C. both A and B are true.
D. neither A nor B is true.
E. This topic was not covered in this chapter.
Which position-versus-time graph
represents the motion shown in the motion
diagram?
Which velocity-versus-time graph goes
with the position-versus-time graph on
the left?
REDO
Which velocity-versus-time graph goes
with the position-versus-time graph on
the left?
Average acceleration
To quantify an object’s change in motion, we define
acceleration:
change in velocity
average acceleration 
change in time
Average acceleration should include direction. The average velocity
of an object during a time interval Δt is a vector.
aavg

v s

t
In one dimension (chapter 2), direction is either + or – (it’s up to
you which real direction + or – actually means). Then, “s” is x or y.
Example problem
Chapter 2 #8 (p. 65)
“s” means x, y or z…whatever direction you are dealing with
1604 Galileo experiments with falling bodies,
especially ones “falling” down an inclined plane.
1607 Finally formulates the equations you see above.
“kinematics”
Using the kinematic (Galileo’s) equations:
• They only apply AFTER motion has begun
• Do not worry about the details of HOW
something got into motion
•As soon as conditions change (a new force
appears, an old force disappears, a collision…)
you need to apply a new set of equations
Example problem
Chapter 2 #14 (p. 66)
Example problem
Chapter 2 #66 (p. 70)
Free Fall
•Free fall technically means that gravity is the
only force acting on the object
•The gravitational force is constant
•Therefore, so is the acceleration, so Galileo’s
equations apply!
• a = “g” = 9.8 m/s2 near the Earth’s surface
IMPORTANT:
g = 9.8 but a can be + 9.8 OR −9.8 depending on
which way you define down to be. It is customary,
and smart, to use − for down!
A 1-pound block and a 100-pound
block are placed side by side at the
top of a frictionless hill. Each is given
a very light tap to begin their race to
the bottom of the hill. In the absence
of air resistance
A. the 1-pound block wins the race.
B. the 100-pound block wins the
race.
C. the two blocks end in a tie.
D. there’s not enough information to
determine which block wins the
race.
Example problem
Chapter 2 #16 (p. 66)
Motion on an Inclined Plane
Example problem
Chapter 2 inclined plane
(not in text)
Calculus and Motion
Read the material in chapter 2 and review your
calculus as necessary.
For now, I will focus on using derivatives more
than integrals.
Calculus and Motion
Example problem
Chapter 2 derivatives and motion
(not in text)