Angular, linear velocity & centripetal acceleration

In summary, the ratio of the centripetal accelerations for the fast and slow spin cycles of a washing machine is 2.83:1. This is found by converting the angular velocities from revolutions per minute to radians per second, calculating the linear velocities, and then applying the centripetal acceleration formula for each cycle. The high speeds of the cycles result in large accelerations, which may seem surprising but are correct.
  • #1
GreatEscapist
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Homework Statement


A washing machine's two spin cycles are 328 rev/min and 542 rev/min. The diameter of the drum is 0.43 m.
What is the ratio of the centripetal accelerations for the fast and slow spin cycles?

Homework Equations


ac=v2/r
linear velocity: v=rw (w is really omega)
angular velocity= change in theta/change in time

I think that's all I need.

The Attempt at a Solution


First I changed the angular velocities from rev/min to rad/s. So, 328 rev/min=34 rad/s, and 542 rev/min=57 rad/s.
I solved for the slow cycle's acceleration first. Since it is in linear velocity instead of angular velocity, i solved for the linear velocities for the slow and fast cycle.
v=rw -> vs=(.215 m)(34 rad/s) -> 7.31 m/s
v=rw -> vf=(.215 m)(57 rad/s) -> 12.3 m/s
Then I plugged these into the centripetal acceleration formula for the slow and fast cycles.
acs=v2/r -> a=(7.31 m/s)(7.31 m/s)/(.215 m) -> 248.54 m/s2
acf=v2/r -> a=(12.3 m/s)(12.3 m/s)/(.215 m) -> 703.67 m/s2There may not be anything wrong with it, but those numbers for the acceleration seem soooooo big. It's easy physics, so I don't know what I'm doing wrong. >:(
 
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  • #2
Yes they are correct. Both those speeds are quite high, so the centripetal accelerations are high as well.
 
  • #3
Oh.
I did this wrong the first time I did it, and I forgot what the answers were (yay spring break)
Thanks. :P
 

1. What is the difference between angular velocity and linear velocity?

Angular velocity is a measure of the rate of change of angular displacement, while linear velocity is a measure of the rate of change of linear displacement. In simpler terms, angular velocity refers to the rotational speed of an object, while linear velocity refers to the speed of an object in a straight line.

2. How are angular velocity and linear velocity related?

Angular velocity and linear velocity are related by the equation v = rω, where v is linear velocity, r is the radius of the circular path, and ω is angular velocity. This means that the linear velocity of an object moving in a circular path is directly proportional to its angular velocity and the radius of the path.

3. What is centripetal acceleration and how is it related to angular and linear velocity?

Centripetal acceleration is the acceleration that an object experiences when moving in a circular path. It is always directed towards the center of the circle and its magnitude is given by a = rω², where r is the radius of the circular path and ω is the angular velocity. This means that as angular velocity and/or radius increase, so does centripetal acceleration.

4. How does centripetal acceleration affect an object moving in a circular path?

Centripetal acceleration is responsible for keeping an object moving in a circular path by continuously changing its direction towards the center of the circle. Without this acceleration, the object would move in a straight line tangent to the circle.

5. Can the magnitude of centripetal acceleration ever be greater than the magnitude of linear velocity?

Yes, the magnitude of centripetal acceleration can be greater than the magnitude of linear velocity when the object is moving in a circular path with a smaller radius. This means that the object is moving at a higher speed in a smaller circle, resulting in a greater centripetal acceleration.

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