Solving Angular Velocity Homework: Mass, Friction & Work

In summary, a puck of mass 0.5kg is moving with a uniform constant motion on a frictionless horizontal table. Its angular frequency is 10 sec-1 and its radius of circular motion is 0.8m. The student then pulls the string down by 0.5m, and the work done can be found by using the equation KE(original) + W = KE(final). However, the solution requires calculating the final kinetic energy, which can be done using the conservation of angular momentum.
  • #1
superaznnerd
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0

Homework Statement


a small puck of mass .5kg is executing Uniform constant motion on a friction free horizontal table. The angular frequency of the puck is 10 sec-1 (counter clockwise) and the radius of the circular motion is .8m. the radius stays fixed as the student holds the string in place. he now pulls the string down .5 m and holds it again in place. what work did he do?


Homework Equations



KE(original)+ W = KE (final)
inertia of hockey puck on string = mr2
w = angular velocity
I = inertia

The Attempt at a Solution


KE(original)+ W = KE (final)
.5(I)w2 +W = KE final
.5 (.5)(.8)2(102) + W = KE final

now i have a problem solving for kinetic energy final...
KE final = .5(.5)(.5)2(102)(w2)
I can't figure out what w (angular velocity) is...
please help!
 
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  • #2
Have you tried using the conservation of angular momentum?
 

FAQ: Solving Angular Velocity Homework: Mass, Friction & Work

What is angular velocity?

Angular velocity is a measure of how fast an object is rotating around a fixed axis. It is typically measured in radians per second (rad/s) or degrees per second (deg/s).

How is angular velocity related to linear velocity?

Angular velocity and linear velocity are related by the radius of the rotation. The linear velocity is equal to the angular velocity multiplied by the radius of the rotation.

How does mass affect angular velocity?

Mass does not directly affect angular velocity. However, the distribution of mass in an object can affect its moment of inertia, which in turn can affect its angular velocity.

What role does friction play in angular velocity?

Friction can slow down or speed up the rotation of an object. If there is no external torque acting on the object, the frictional torque will cause the angular velocity to decrease. However, if there is an external torque, friction can help maintain the angular velocity by counteracting the external torque.

How is work related to angular velocity?

Work is a measure of the energy transferred to or from an object. In the case of angular velocity, work can be done by or on an object to change its angular velocity. The work done is equal to the torque applied multiplied by the change in angle.

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