Transcript Introduction to ENGR 111 - Physics & Astronomy | SFASU

Physics 108
Introduction to
Engineering/Physics
Objectives of Physics 108
Learn about the different
engineering disciplines
Learn about professionalism in
engineering
Become a better problem solver
Develop teaming skills
Why Active/Collaborative Learning?
Active
Countless studies have shown improvement in:
short-term retention of material,
long-term retention of material,
ability to apply material to new situations
Collaborative
Engineering teams are used in industry and
usually make the best use of time
Consulting
Why Physics?
Architecture
Mechanical
Astronomy
Engineering
Electrical
Civil
Review
Units of
Measure
See Notes
Chapter 1
Introduction to
Vectors
Scalar Quantity
a quantity that has magnitude but
not direction
Vector Quantity
a quantity that has both
magnitude and direction
Vector Quantities
force
e.g. 20 Newtons Eastward
velocity
e.g. 20 meters/second North
acceleration
e.g. 9.8 m/s2 downward
Scalar Quantities
length
e.g. 93,000,000 miles
mass
e.g. 180 kg
speed
e.g. 186,000 miles/second
Vector
an arrow drawn to scale used
to represent a vector quantity
vector notation
F
Resultant
the sum of vectors
Methods of Vector Addition
tip-to-tail method (polygon
method)
component method
Tip-to-Tail Method
Example 1: Add these vectors using the
tip-to-tail method.
+
A
B
Tip to Tail Method
A+ B= C
B
C
A
Component Method
y

A

Ay

Ax
x
Notes on Components
Components are vectors

A

Ax
Ay



Ax  A y  A
Lengths of Components

A
q

Ax
Ax = A cos q
Ay = A sin q

Ay
If Components are Known
A A A
2
x
2
y
2
q  Tan (Ay /Ax )
1
Unit Vector
magnitude of 1 and a direction
ˆi, ˆj, kˆ
ˆ
ˆ
ˆ
R  R xi  R y j  R zk