Transcript Chapter 1

Chapter 1 – Introduction and Math Concepts
Cover: 1.1-1.9
4 STEPS TO PROBLEM SOLVING
1.
UNDERSTAND the question.
2.
SIMPLIFY (draw a picture, weed
out the inconsequentials)
3.
TRY!! (this requires thinking AND
writing; don’t give up completely, but
breaks are good!)
4.
Does the answer MAKE SENSE?
If it doesn’t, it’s probably wrong.
1.1 – The Nature of Physics
1.2 – Units
SI Units (kilogram, meter, second)
Metric Prefixes (Kilo, Centi, Milli, Micro,
Nano, etc)
Do the prefix scale on the board…
1.3 – The Role of Units in Problem Solving
Know how to convert units
(Conversion Factors!!)
Example 1: Convert 55 mi/hr to m/s.
Example 2: Convert 60 p.s.i. to kg/cm2
Dimensional Analysis (pg. 6)
1.4 – Trigonometry
Right triangles ONLY
h0 opp.
sin   
h hyp.
h0 opp.
tan  

ha adj.
ha adj.
cos  

h hyp.
h  ho  ha
2
2
2
1.4 – Trigonometry
Example 3: How tall is the
building?
Be sure your calculator is in
degree mode!
1.4 – Trigonometry
Example 4: At what angle does
the lakefront drop off?
4 STEPS TO PROBLEM SOLVING
1.
UNDERSTAND the question.
2.
SIMPLIFY (draw a picture, weed
out the inconsequentials)
3.
TRY!! (this requires thinking AND
writing; don’t give up completely, but
breaks are good!)
4.
Does the answer MAKE SENSE?
If it doesn’t, it’s probably wrong.
ASSIGNMENT:
Chapter 1
Read: 1.1 – 1.4
Answer: Problems #1 – 4; 11,12,16,17
on pg. 21/22
ALSO – Signed Syllabus.
1.5 – Scalars & Vectors
Scalar – measurement with a single
number (magnitude)
Vector – measurement with a magnitude
and a direction.
tail
head
1.5 – Scalars & Vectors
Vectors are…
drawn to scale,
printed in bold or with an arrow above.

A  5 m, east

B  10 m, east
1.5 – Scalars & Vectors
2 Ways to Express Vectors
1) magnitude-angle form

8.6m @ 37 N of E
2) x-y component form


6.87m( x )  5.18m( y )
1.6 – Adding & Subtracting Vectors
Vectors are added ‘tail-to-head’ to
form a Resultant (R).
A & B are colinear; R is no problem
1.6 – Adding & Subtracting Vectors
A & B are perpendicular; R is no problem
1.6 – Adding & Subtracting Vectors
A & B are neither colinear nor
perpendicular; what is R?
1.7 – The Components of a Vector
All vectors can be resolved (broken
down) into x and y components (parts)



Ax  Ay  A
1.8 – Adding and Subtracting Vectors II
2 methods of adding/subtracting
vectors that are NOT colinear or
perpendicular.
1) Graphical (draw to scale, use ruler & protractor)
2) Analytical (resolve each vector into components
and add)
1.8 – Adding and Subtracting Vectors II
Example: Determine the resultant of
these two vectors.
A = 145m @ 20.0° E of N
B = 105m @ 35.0° S of E
1. Draw a rough sketch of the 2 vectors placed
‘tail-to-head’
2. Break each vector into X and Y components.
3. Add the X’s and Y’s together.
ASSIGNMENT:
Chapter 1
Read 1.5 – 1.8,
Answer Problems #21,24,25,31,32, 33,36,42