lecture 12 newton’s laws of motion. amount that the irs has spent since 2006 on an outsourced...
Post on 19-Dec-2015
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TRANSCRIPT
Amount that the IRS has spent since 2006 on an outsourced program to
collect unpaid taxes: $87,000,000
QUIZ
• Find this vector’s magnitude and angle with respect to the positive x axis and draw it
• Find the x- and y-components of the vector
20 / 40 /x yv m s v m s
0(2 ,45 below +x-axis)d km
What Causes Motion?
In the absence of any forces acting on it, an object will continue moving forever. Motion needs no “cause.”
Slide 4-8
Exercise
A ball, hanging from the ceiling by a string, is pulled back and released. Identify the forces acting on it just after its release.
Slide 4-21
Example
An elevator, lifted by a cable, is going up at a steady speed. • Identify the forces acting on the elevator. • Is T greater than, equal to, or less than w? Or is there not
enough information to tell?
Slide 4-23
Free body diagrams
• Make diagram of object showing all forces acting on it (as vectors). For now object will be represented by a point.
• Decide on the x and y-axes• Find x- and y-components of each force• Find
• Show FNET on diagram
, 1 2
, 1 2
...
...NET x x x
NET y y y
F F F
F F F