Shadow of vertical circle on wall?

  • #1
A ball is spun in a vertical circle on a string. A light is shining from the side of the circle so that a shadow of the balls motion is shown on a wall behind it. The shadow is simply a circle moving up and down in a straight line (I can't attach the image). The amplitude of the shadow is 0.5m and it takes 1s for the shadow to move from the bottom to the top and back. What is the angular velocity, tangential velocity, and centripetal acceleration of the ball?



Homework Equations



a = v^2/r
w=2pi/T
v=rw

x=asinwt
a=-w^2asinwt
v=wAcoswt
v^2=w^2(A^2-x^2)


The Attempt at a Solution



Well I'm guessing this is something to do with UCM being projected onto the diameter, as in https://www.physicsforums.com/archive/index.php/t-17536.html"thread. From there however, I don't really know where to start!
 
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Answers and Replies

  • #3
nobody knows?
 
  • #4
You know the time period. From there find angular velocity. Since you also have radius find the rest. The language of the question suggests that we have to assume constant circular velocity.
 
  • #5
tiny-tim
Science Advisor
Homework Helper
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hi donkeycopter! :smile:

(try using the X2 icon just above the Reply box :wink:)

how far away is the light?

is it "infinitely" far, like the Sun? :confused:
 
  • #6
I think we will have to assume that if its not given
 

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