Horizontal coefficient of restitution

AI Thread Summary
The discussion revolves around calculating the horizontal coefficient of restitution (CoR) for a tennis ball, alongside the already determined vertical CoR of 0.760. The original poster expresses confusion regarding the existence and calculation of the horizontal CoR, noting that their textbook does not address it. Participants clarify that while the horizontal CoR is less commonly referenced, it can be obtained similarly to the vertical CoR by using horizontal velocity components. The conversation emphasizes the relationship between bounce height, time, and horizontal distance traveled, suggesting that the horizontal CoR is tied to the vertical CoR. Ultimately, the horizontal CoR can be calculated using the same principles as the vertical one, focusing on the respective horizontal components.
Psych Berry
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Homework Statement


I'm supposed to determine the [vertical] coefficient of restitution of a tennis ball, and the horrizontal coefficient of restitution, and if possible produce an equation or ratio connecting the two.

Vertical CoR: 0.760
Constant x-component velocity: 0.853 m/s

Homework Equations


sqrt (h2/h1) = |v2/v1|


The Attempt at a Solution


I've already calculated the [vertical] coefficient of restitution, and googled to find out that my answer is consistent with that of standard tennis ball.
At this point I just don't know how to calculate the horrizontal CoR. My textbook and lab manual don't mention it, and I can't figure out what relationship they would have.
Can anyone help me out here?
 
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From what I am told, the coefficient of restitution for when objects collide in two planes, is found by taking the ratio of the vertical component of the velocities. So I don't think there is such thing as a horizontal coefficient of restitution.
 
rock.freak667 said:
From what I am told, the coefficient of restitution for when objects collide in two planes, is found by taking the ratio of the vertical component of the velocities. So I don't think there is such thing as a horizontal coefficient of restitution.

Maybe that's true, my lab manual where the questions are stated is definitely not written by people with doctorates in physics. But that's merely terminology. It wouldn't change my question.

If there is no such thing as "horizontal coefficient of restitution" then what would the corresponding horizontal ratio be?

Thinking about it more I assume it would be based off the regular coefficient of restitution, since horizontal velocity is constant, therefore the distance traveled per bounce is a function of time, and the time of each bounce is dependent on the max height reached, which is in turn dependent on the CoR. But I don't know how to state that in an equation, or if I'm even on the right track.
 
hi rock.freak667! :smile:

yeah, I've never heard of it before either …

but I just googled it, and apparently it does exist (I couldn't be bothered to read about it though :rolleyes:)
 
tiny-tim said:
hi rock.freak667! :smile:

yeah, I've never heard of it before either …

but I just googled it, and apparently it does exist (I couldn't be bothered to read about it though :rolleyes:)

Well then, if it exists can anyone enlighten me as to how to obtain it?
 
Psych Berry said:
Well then, if it exists can anyone enlighten me as to how to obtain it?

Well according to http://www2.physics.umd.edu/~mfuhrer/course/spr02/AJP/AJP00482.pdf" , it seems that you obtain the horizontal coefficient of restitution the same way you get the vertical one. You just use the horizontal components instead of the vertical ones it seems.
 
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