Question

In the figure the lower disk, of mass 440 g and radius 3.7 cm , is rotating at 180 rpm on a frictionless shaft of negligible radius. The upper disk, of mass 280 g and radius 2.0 cm , is initially not rotating. It drops freely down onto the lower disk, and frictional forces bring the two disks to a common rotational speed. A) Find the common speed. B) Find the fraction of the initial kinetic energy lost to friction.

Answer #1

A disk (mass of 3 kg, radius 30 cm) is rotating with an angular
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disks are dropped so that they share a rotational axis, and they
stick together. The moment of inertia of a disk is 1/2mr^2. What is
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A 2.15-kg, 16.0-cm radius, high-end turntable is rotating freely
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1)
Assuming that the gum sticks where it lands, and that the
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In the figure, a small disk of radius r=1.00 cm has been glued
to the edge of a larger disk of radius R=6.00 cm so that the disks
lie in the same plane. The disks can be rotated around a
perpendicular axis through point O at the center of the larger
disk. The disks both have a uniform density (mass per unit volume)
of 1.40 × 103 kg/m3 and a uniform thickness of 7.00 mm. What is the
rotational inertia...

In the figure, a small disk of radius r=2.00 cm has
been glued to the edge of a larger disk of radius R=7.00
cm so that the disks lie in the same plane. The disks can be
rotated around a perpendicular axis through point O at the
center of the larger disk. The disks both have a uniform density
(mass per unit volume) of 1.40 × 10^3 kg/m3 and a
uniform thickness of 6.00 mm. What is the rotational inertia...

Disk A, with a mass of 2.0 kg and a radius of 90 cm , rotates
clockwise about a frictionless vertical axle at 40 rev/s . Disk B,
also 2.0 kg but with a radius of 50 cm , rotates counterclockwise
about that same axle, but at a greater height than disk A, at 40
rev/s . Disk B slides down the axle until it lands on top of disk
A, after which they rotate together. After the collision, what...

An electric sander consisting of a rotating disk of mass 0.75 kg
and radius 10 cm rotates at 15 rev/sec. When applied to a rough
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a) What is the final rotational kinetic energy of the rotating
disk?
b) How much has its rotational kinetic energy [in J]
decreased?

A light cord is wrapped about a disk with radius of 30 cm and a
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a. What was the torque applied to the disk?
b. What was the angular acceleration of the disk?
c. Calculate the angular velocity of the disk and the total
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d. Show that the...

A turntable has a radius R and mass M (considered as a disk) and
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The pendulum in the figure consists of a uniform disk with
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pendulum? (c)Calculate the period of
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