ENGR 230 Dynamics Section 18

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ENGR 230 Dynamics Section 18
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Lecture Example (Problem 18-5) At the instant
shown, link AB has angular velocity ?AB 2
rad/sec. If each link is considered as a uniform
slender bar with weight density of 0.5 lb/in,
determine the total kinetic energy of the system.

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Lecture Example (Problem 18-11) A yo-yo has
weight of 0.3 lb and radius of gyration kO0.06
ft. If it is released from rest, determine how
far it must descend in order to attain angular
velocity ? 70 rad/sec. Neglect the mass of the
string and assume that the string is wound around
the central peg such that the mean radius at
which it unravels is r 0.02 ft.
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Lecture Example (Problem 18-33) A ball of mass
m and radius r is cast onto the horizontal
surface such that it rolls without slipping.
Determine the minimum speed vG of its mass center
G so that it rolls completely around the loop of
radius R r without leaving the track.
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Lecture Example (Problem 18-47) The compound
disk pulley consists of a hub and attached outer
rim. If it has mass, mdisk3kg and radius of
gyration kG45mm determine the speed of block A
after A descends distance 0.2m from rest. Blocks
A and B each have a mass mb2kg. Neglect the mass
of the cords.
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Lecture Example (Problem 18-57) The assembly
consists of two 3 ft. bars of weight 8 lb. which
are pin connected to the two disks with a radius
of 0.5 ft. and a weight of 10 lb. If the bars are
released from rest at ? 60?, determine their
angular velocities at the instant ? 0?. Assume
the disks roll without slipping.