Shadow of vertical circle on wall?

In summary, a ball is spun in a vertical circle on a string and a light shining from the side creates a shadow on a wall behind it. The shadow moves in a straight line with an amplitude of 0.5m and takes 1s to move from the bottom to the top and back. To find the angular velocity, tangential velocity, and centripetal acceleration of the ball, the equations a = v^2/r, w=2pi/T, and v=rw can be used. The question suggests that we have to assume constant circular velocity and the assumption of the light being infinitely far away, like the Sun, may need to be made.
  • #1
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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  • #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
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
 

FAQ: Shadow of vertical circle on wall?

What is a shadow of vertical circle on wall?

A shadow of vertical circle on wall is a phenomenon that occurs when a circular object, such as a ball or a coin, is placed in front of a light source and its shadow is projected onto a flat surface, such as a wall. The shape of the shadow will depend on the angle of the light source and the position of the object.

How is the shadow of vertical circle on wall formed?

The shadow of vertical circle on wall is formed when light rays from a single light source hit the circular object and are blocked by it, creating an area of darkness behind the object. This area of darkness is what we perceive as the shadow on the wall.

Why does the shadow of vertical circle on wall change shape?

The shape of the shadow of vertical circle on wall changes because of the changing position and angle of the light source in relation to the object. As the light source moves or the object is rotated, the shape and size of the shadow will also change.

How can I calculate the size of the shadow of vertical circle on wall?

The size of the shadow of vertical circle on wall can be calculated using basic trigonometry. By measuring the distance from the light source to the object and from the object to the wall, and using the angle of incidence, you can calculate the size of the shadow using the tangent function.

What factors affect the shadow of vertical circle on wall?

The size and shape of the shadow of vertical circle on wall can be affected by several factors, including the distance between the object and the light source, the distance between the object and the wall, the size and shape of the object, and the angle of incidence of the light. The type of light source and the surface of the wall can also have an impact on the appearance of the shadow.

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