exam info
8:30 friday 11
5 conceptual questions (multiple choice, short response) = 20 pt
based off of response questions, FOC problems, workshops
2 written problems (30 pt)
based off of example and i
1/13/16
The Sciences
laws of nature: an effort to understand through discovery of regularities
laws describe what CAN happen
theories developed to explain what DOES happen
all sciences united by this
ideal pulley
change direction of tension, not magnitude
(frictionless)
A climber with a mass Mc hangs from a vertical massless rope. the rope goes over a pulley and,
after traveling horizontally for a
1/20
chapter 2
Position Vectorsalways start at origin
magnitude of vectors is distance from origin
with direction gives location
Notation- r= rxX^ + ryY^
distance greater than or equal to 0
rx,ry can
Work in 6
force applied over a distance
W=Fdcos
Work in 7
impulse - force applied over time
J=Ft
units: Newtons*seconds = Kg m/s
Impulse-Momentum Theoremsince F=ma and a=v/t
J=Ft = (ma)t=m(v/t)t= mv
d
Dynamics
explains kinematics
forces cause acceleration
contact forces(push/pull, friction, normal)
non-contact forces
Newtons First Law
no force- no acceleration
constant velocity
if the net force on
Work and Kinetic Energy
You pull on a suitcase that slides across a frictionless floor. You apply a force at some angle
above the horizontal direction. How fast is the suitcase going after you pull on
Rotational Kinematics
Quantifying rotational motion
Angular PositionDefined by , SI units: radians
Dimensionless
1 rad = angle for which arc length of a circle = radius
2rad in a circle = 360
1 rad =
Review
climber hanging from a rope- tension
not in contact with any other surfaces-no normal force
T1, T2 do not make a 90 degree angle - do not use rotated coordinate system
Fx=T2x-T1x=maz=0
T2cos20-
Chapter 3
I throw a ball upward at a speed of 20m/s. How high has the ball done in half the time it takes to
get tot the top of its motion?
Known:
Vo=20m/s
Yo=0m
a=-g(-9.81)
Vtop=0m/s
Need:
Ttop
t=1/2
exam 1 info
5 conceptional
2 written
focus on concept hw questions- write out reason for correct answer
rework example, hw, and workshop
not on exam (3.4) relative motion and (4.7) gravitation
1/15
Scalars
magnitudes with units
(height, weight, distance, speed, temp)
magnitudes always positive, direction makes no difference
vector components
can break vectors into components
(3 blocks east
Rotational Kinetic Energy
Translational (linear)
KE=1/2mv^2
Rotational- let v=v^2
KE=1/2mvt^2
=1/2m(r)^2
=1/2*(mr^2)^2
depends on distribution of mass about axis of rotation
Multiple objects rotating