A uniform-density 8 kg disk of radius 0.25 m is mounted on a nearly frictionless axle. Initially it is not spinning. A string is wrapped tightly around the disk, and you pull on the string with a constant force of 41 N through a distance of 0.9 m. Now what is the angular speed

Question

Whiskey

Physics

28 April, 16:10

A uniform-density 8 kg disk of radius 0.25 m is mounted on a nearly frictionless axle. Initially it is not spinning. A string is wrapped tightly around the disk, and you pull on the string with a constant force of 41 N through a distance of 0.9 m. Now what is the angular speed

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Dirt · Answer 1

moment of inertia of the disc I = 1/2 m r²

=.5 x 8 x. 25²

=.25 kg m²

The wok done by force will be converted into rotational kinetic energy

F x d = 1/2 I ω²

F is force applied, d is displacement, I is moment of inertia of disc and ω

is angular velocity of disc

41 x. 9 = 1/2 x. 25 ω²

ω² =.25

ω = 17.18 rad / s