Question

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 wooden wall the rotation rate decreases by 30.0%.

a) What is the final rotational kinetic energy of the rotating disk?

b) How much has its rotational kinetic energy [in J] decreased?

Answer #1

A disk of mass 1.5 kg and radius 65 cm with a small mass of 0.04
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A uniform, solid sphere of mass 2.6 kg and diameter 33 cm is
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A) What is the kinetic energy of rotation?
B) If an additional 1.74 J of energy are supplied to the
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your answer in rev/min.

A disk (mass of 3 kg, radius 30 cm) is rotating with an angular
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is rotating at w= -7 rad/s is dropped on top of the first disk. The
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 light cord is wrapped about a disk with radius of 30 cm and a
mass of 1.4 kg. the disk is free to rotate about an anxle. The cord
is pulled with a tension T= 1.5 newtons for 10 sec.
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
angular distance turned after 10 secs
d. Show that the...

Disk A, with a mass of 2.0 kg and a radius of 60 cm , rotates
clockwise about a frictionless vertical axle at 40 rev/s . Disk B,
also 2.0 kg but with a radius of 40 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.

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
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perpendicular to the disk at its center. Rotating flywheels provide
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perpendicular to the disk at its center. Rotating flywheels provide
a means for storing energy in the form of rotational kinetic energy
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In the figure the lower disk, of mass 440 g and radius 3.7 cm ,
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A solid uniform disk of mass M = 9.6 kg and radius R = 21 cm
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1)
What is the acceleration of...

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