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Constant Angular Velocity Problem

  • Thread starter math_girl
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  • #1
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Homework Statement


I encountered the following problem and I don't know where to begin or what formula to use... An object is moving in a circular path with a radius of 4.00 m. If the object moves through an arc length of 3.16m, then find the angular displacement?


Homework Equations


I wish I knew.


The Attempt at a Solution


Any help would be great thanks!
 

Answers and Replies

  • #2
LowlyPion
Homework Helper
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Welcome to PF.

What is the circumference of a circle with radius 4?

And what percentage of the circumference does 3.16 represent?

That percentage of 360° then ...
 
  • #3
PhanthomJay
Science Advisor
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Gold Member
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Just look up (then study) the relationship between arc length (s), radius (r) and angular displacement (theta). Note that theta is in radians. If you have no textbook, try Google.
 
  • #4
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Welcome to PF.

What is the circumference of a circle with radius 4?

And what percentage of the circumference does 3.16 represent?

That percentage of 360° then ...
so I got the following figured out, circumerence is 25.13

to find the percentage of the circumference that 3.16 represents should I take 3.16/25.13? If so that number is .126, than what should I do with figuring out the percentage of 360°?
 
  • #5
LowlyPion
Homework Helper
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so I got the following figured out, circumerence is 25.13

to find the percentage of the circumference that 3.16 represents should I take 3.16/25.13? If so that number is .126, than what should I do with figuring out the percentage of 360°?
What you determined is the fraction of the circumference. Since there are 360 degrees in a full circle or alternatively there are 2*π radians in a circle ...

If you want degrees, then multiply by 360.

If you want it in radians, there are 2*π (2*3.1415), then multiply .126*6.283.
 
  • #6
6
0
What you determined is the fraction of the circumference. Since there are 360 degrees in a full circle or alternatively there are 2*π radians in a circle ...

If you want degrees, then multiply by 360.

If you want it in radians, there are 2*π (2*3.1415), then multiply .126*6.283.
thanks thats what I needed to figure it out! Thanks
 
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