A ball of mass m is thrown with a velocity v at a disk

AI Thread Summary
The discussion centers on calculating the total initial angular momentum of a ball of mass m thrown at a disk of mass M, which sticks to the disk upon impact. The relevant equation for angular momentum, L = r x p, is utilized, with the cross product indicating the direction of momentum. The specific angular momentum calculated is given as (0, 0, -Rmv), assuming the axis of rotation is through the center of the disk. The right-hand rule is confirmed as a method to determine the direction of angular momentum. The solution is affirmed as correct based on the provided definitions and calculations.
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Homework Statement



A ball of mass m is thrown with a velocity v at a disk of mass M which sticks to the rim on impact.https://s3.lite.msu.edu/res/msu/perl_author/P3_PRELECTURE/L_CONSERVATION/IMAGES/CQ1.png

For the system of the ball and disk, what is the total initial angular momentum about the axis?[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,0,Rmv[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png
[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,0,−Rmv[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png
[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,−Rmv,0[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png
[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,Rmv,0[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png
[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,0,0[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png[/B]

Homework Equations


Cross Product

The Attempt at a Solution



τ⃗ A=r⃗ A×F⃗
Cross Product
[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,0,−Rmv[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png
 

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What is your specific question about this question?
 
Am I correct?
 
Yes, [PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png0,0,−Rmv[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.png, using the definition of angular momentum as L=r x p and the right-hand rule (presuming the axis is through the axis of the disk).
 
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Right hand rule?
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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