Physics 218: Mechanics

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Physics 218 Mechanics
Instructor Dr. Tatiana Erukhimova Lecture 41
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Please turn in your optional homework
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If the block is pulled a distance x1 to the right
and released from rest, how long will it take the
block to return to its equilibrium position?
How does this time change if the displacement
is increased from x1 to 2x1? How fast will the
block be moving at its equilibrium position for
the x1 displacement?
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A bullet of mass m is fired with velocity of
magnitude into a block of mass M. The
block is connected to a spring constant k and
rests on a frictionless surface. Find the
velocity of the block as a function of time.
(Assume the bullet comes to rest infinitely
quickly in the block, i.e. during the collision
the spring doesnt get compressed.)
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Simple pendulum
How long does it take to return to the
equilibrium?
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Resonance
amplitude
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Frames of reference
An airplane flies from Houston to Tokyo in 14
hours, while the return trip takes only 10 hours.
Find the wind velocity and plane speed with
respect to air, if the distance is 7000 miles.
W
H
T
- airplane speed with respect to air.
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In the freely-falling elevator cabin you dont
feel any effects of gravity! You and all objects
around you experience the same acceleration.
In outer space you can imitate the effect of
gravity by acceleration.
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Final exam room 204 MPHY, 1030 am - 1230 pm,
Wednesday, December 12.
Help Sessions By appointment Thursday, December
6th, time ?? 204 MPHY
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Newtons First Law Second Law
Third Law
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Kinematics
If
is given, you can find
and
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Work Energy Theorem
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does NOT depend on path!
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Mechanical energy is conserved!
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Conservation of Momentum
If the collision is perfectly elastic, the
kinetic energy is conserved!
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Circular Motion
y
x
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Conservation of Angular Momentum
For symmetrical objects rotating about their axis
of symmetry
R
m2
Second Law
m1
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Harmonic Motion
Resonance