Chapter 2
Motion along a (straight) line
1-D motion
Position and Displacement
Consider object (thing) moving along straight line
Choose x axis / line
Choose positive direction (x increasing)
Choose origin (point where x = 0)
Must make these choices to pr
Projectile Motion
Trajectory is a parabola (Pg 69)
vix = vicos, viy = visin
vy = 0 at max height, but
vx = constant
Range defined as coming back to initial height y = 0
Angle of trajectory
at any point: tan = vy/vx
Chpt 4: Force and Newtons Laws
From 168
Class 4, 9/5
Sections 001 & 004 (David Bowen)
Back Channel http:/TodaysMeet.com/Framed
WebAssign
Exams will be based on credit and non-credit WebAssign
problems, transformed
Many Non-Credit problems are easier a good starting
point
If you are having troub
Free Fall
Free fall refers to an object released and falling all by itself, just
by gravity (e.g. neglecting air resistance)
By experiment, free fall occurs with a constant downward
acceleration of 9.80 m/s2
Close to earth, independent of position, motio
Chapter 3 - Vectors
Wow is this important!
Chapter 3
Motion in 2D: Vectors
Define a new type of thing a vector, has both magnitude (+ve
value, units) and direction
Algebraic symbol: bold with arrow above
Graphical symbol: arrow
Can be moved / without cha
Constant Acceleration
Intro: what is acceleration?
Consider an object moving along a straight line
Object anything
Choose an x axis (like a ruler) along the line
Axis direction: direction in which x increases
Position of object = value of x
Displacement
Chpt 4: Force and Newtons Laws
From 1687, tested continuously since (passed!)
Three Laws, start with second
About me most important info up front
N2:
applies to an object (thing)
m = mass (quantity of matter) of object (kg)
are forces (vectors), all forc
Acceleration
As with velocity, define average (aav,x) and instantaneous (ax)
(instantaneous) acceleration ax
Average acceleration aav,x vx/t
ax = slope of vx-t plot, rate of change of vx
ax positive, vx increasing (no info about vx itself)
ax = 0, vx = c
Example 1
A bullet starts from rest and accelerates at a constant rate down
a gun barrel 0.8 m long and emerges with a velocity of 1000
m/s.
Find its acceleration.
How long does the trip down the gun barrel take?
Dx, Dt, vix, vfx, ax: which 3 variables a
Example: A mass m is hung by
an ideal rope from a frictionless
pulley as in the sketch to the right.
Find the net force on the mass.
Fnet = 2T up + mg down
Example: Bird on a Wire
A bird with mass 1.43 kg
is sitting in the middle of
telephone wire. The p