Shadow of vertical circle on wall?

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Homework Help Overview

The problem involves a ball being spun in a vertical circle, with a light source casting a shadow of its motion onto a wall. The shadow's motion is described as a circle moving up and down along a straight line, with specific parameters provided, such as amplitude and time period. The goal is to determine the angular velocity, tangential velocity, and centripetal acceleration of the ball.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between uniform circular motion and the projection of that motion onto a wall. Some suggest using known equations related to circular motion, while others question the distance of the light source and its implications on the shadow's characteristics.

Discussion Status

There is an ongoing exploration of the problem, with some participants offering guidance on how to approach finding angular velocity based on the time period. However, there is no explicit consensus on the assumptions regarding the light source or the nature of the motion.

Contextual Notes

Participants note the lack of information about the distance of the light source, which could affect the interpretation of the shadow's motion. There is also an assumption of constant circular velocity suggested in the discussion.

donkeycopter
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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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nobody knows?
 
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.
 
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:
 
I think we will have to assume that if its not given
 

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