Is Angular momentum conserved in Impure rolling












5












$begingroup$


In a situation where a disk is rolling WITH slipping on the ground i.e velocity of centre of mass is greater than $romega$, is angular momentum conserved about a point on the ground.



What confuses me is that friction decelerates the disk to make $v_{com} = romega$ and in this process some velocity is lost so according to formula of angular momentum $L=mvr$,about a point on the ground $L$ decreases as $v$ decreases.



But since friction is also acting about a point on the ground, torque about a point on the ground is zero, so then how would angular momentum change.



edit:this question is about applying conservation of angular momentum in rolling with slipping.










share|cite|improve this question









New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$








  • 1




    $begingroup$
    Possible duplicate of Is $v$ not always equal to $omega r$ in angular motion?
    $endgroup$
    – Mick
    14 hours ago












  • $begingroup$
    Only if the sum of the external torque is zero the angular momentum is conserved
    $endgroup$
    – Eli
    8 hours ago
















5












$begingroup$


In a situation where a disk is rolling WITH slipping on the ground i.e velocity of centre of mass is greater than $romega$, is angular momentum conserved about a point on the ground.



What confuses me is that friction decelerates the disk to make $v_{com} = romega$ and in this process some velocity is lost so according to formula of angular momentum $L=mvr$,about a point on the ground $L$ decreases as $v$ decreases.



But since friction is also acting about a point on the ground, torque about a point on the ground is zero, so then how would angular momentum change.



edit:this question is about applying conservation of angular momentum in rolling with slipping.










share|cite|improve this question









New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$








  • 1




    $begingroup$
    Possible duplicate of Is $v$ not always equal to $omega r$ in angular motion?
    $endgroup$
    – Mick
    14 hours ago












  • $begingroup$
    Only if the sum of the external torque is zero the angular momentum is conserved
    $endgroup$
    – Eli
    8 hours ago














5












5








5


1



$begingroup$


In a situation where a disk is rolling WITH slipping on the ground i.e velocity of centre of mass is greater than $romega$, is angular momentum conserved about a point on the ground.



What confuses me is that friction decelerates the disk to make $v_{com} = romega$ and in this process some velocity is lost so according to formula of angular momentum $L=mvr$,about a point on the ground $L$ decreases as $v$ decreases.



But since friction is also acting about a point on the ground, torque about a point on the ground is zero, so then how would angular momentum change.



edit:this question is about applying conservation of angular momentum in rolling with slipping.










share|cite|improve this question









New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




In a situation where a disk is rolling WITH slipping on the ground i.e velocity of centre of mass is greater than $romega$, is angular momentum conserved about a point on the ground.



What confuses me is that friction decelerates the disk to make $v_{com} = romega$ and in this process some velocity is lost so according to formula of angular momentum $L=mvr$,about a point on the ground $L$ decreases as $v$ decreases.



But since friction is also acting about a point on the ground, torque about a point on the ground is zero, so then how would angular momentum change.



edit:this question is about applying conservation of angular momentum in rolling with slipping.







newtonian-mechanics angular-momentum rotational-dynamics






share|cite|improve this question









New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|cite|improve this question









New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|cite|improve this question




share|cite|improve this question








edited 11 hours ago









Qmechanic

106k121941217




106k121941217






New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 15 hours ago









Lelouche LamperougeLelouche Lamperouge

384




384




New contributor




Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Lelouche Lamperouge is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 1




    $begingroup$
    Possible duplicate of Is $v$ not always equal to $omega r$ in angular motion?
    $endgroup$
    – Mick
    14 hours ago












  • $begingroup$
    Only if the sum of the external torque is zero the angular momentum is conserved
    $endgroup$
    – Eli
    8 hours ago














  • 1




    $begingroup$
    Possible duplicate of Is $v$ not always equal to $omega r$ in angular motion?
    $endgroup$
    – Mick
    14 hours ago












  • $begingroup$
    Only if the sum of the external torque is zero the angular momentum is conserved
    $endgroup$
    – Eli
    8 hours ago








1




1




$begingroup$
Possible duplicate of Is $v$ not always equal to $omega r$ in angular motion?
$endgroup$
– Mick
14 hours ago






$begingroup$
Possible duplicate of Is $v$ not always equal to $omega r$ in angular motion?
$endgroup$
– Mick
14 hours ago














$begingroup$
Only if the sum of the external torque is zero the angular momentum is conserved
$endgroup$
– Eli
8 hours ago




$begingroup$
Only if the sum of the external torque is zero the angular momentum is conserved
$endgroup$
– Eli
8 hours ago










1 Answer
1






active

oldest

votes


















6












$begingroup$

If there is slipping and friction you now have to deal with an accelerating (non-inertial) frame of reference and axis of rotation.

To use Newton's laws of motion in the non-inertial frame of reference a pseudo-force has to be introduced which acts at the centre of mass, has a magnitude equal to the frictional force and acts in the opposite direction to the frictional force.

That pseudo-force produces a torque about the point of contact with the ground which changes the angular momentum of the disc about that point.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    ohh that makes sense. thanks a lot :)
    $endgroup$
    – Lelouche Lamperouge
    12 hours ago












  • $begingroup$
    Where this pseudo-force comes from?
    $endgroup$
    – Eli
    9 hours ago










  • $begingroup$
    @Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
    $endgroup$
    – Farcher
    9 hours ago











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "151"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});






Lelouche Lamperouge is a new contributor. Be nice, and check out our Code of Conduct.










draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f466039%2fis-angular-momentum-conserved-in-impure-rolling%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









6












$begingroup$

If there is slipping and friction you now have to deal with an accelerating (non-inertial) frame of reference and axis of rotation.

To use Newton's laws of motion in the non-inertial frame of reference a pseudo-force has to be introduced which acts at the centre of mass, has a magnitude equal to the frictional force and acts in the opposite direction to the frictional force.

That pseudo-force produces a torque about the point of contact with the ground which changes the angular momentum of the disc about that point.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    ohh that makes sense. thanks a lot :)
    $endgroup$
    – Lelouche Lamperouge
    12 hours ago












  • $begingroup$
    Where this pseudo-force comes from?
    $endgroup$
    – Eli
    9 hours ago










  • $begingroup$
    @Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
    $endgroup$
    – Farcher
    9 hours ago
















6












$begingroup$

If there is slipping and friction you now have to deal with an accelerating (non-inertial) frame of reference and axis of rotation.

To use Newton's laws of motion in the non-inertial frame of reference a pseudo-force has to be introduced which acts at the centre of mass, has a magnitude equal to the frictional force and acts in the opposite direction to the frictional force.

That pseudo-force produces a torque about the point of contact with the ground which changes the angular momentum of the disc about that point.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    ohh that makes sense. thanks a lot :)
    $endgroup$
    – Lelouche Lamperouge
    12 hours ago












  • $begingroup$
    Where this pseudo-force comes from?
    $endgroup$
    – Eli
    9 hours ago










  • $begingroup$
    @Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
    $endgroup$
    – Farcher
    9 hours ago














6












6








6





$begingroup$

If there is slipping and friction you now have to deal with an accelerating (non-inertial) frame of reference and axis of rotation.

To use Newton's laws of motion in the non-inertial frame of reference a pseudo-force has to be introduced which acts at the centre of mass, has a magnitude equal to the frictional force and acts in the opposite direction to the frictional force.

That pseudo-force produces a torque about the point of contact with the ground which changes the angular momentum of the disc about that point.






share|cite|improve this answer









$endgroup$



If there is slipping and friction you now have to deal with an accelerating (non-inertial) frame of reference and axis of rotation.

To use Newton's laws of motion in the non-inertial frame of reference a pseudo-force has to be introduced which acts at the centre of mass, has a magnitude equal to the frictional force and acts in the opposite direction to the frictional force.

That pseudo-force produces a torque about the point of contact with the ground which changes the angular momentum of the disc about that point.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered 12 hours ago









FarcherFarcher

50.7k338105




50.7k338105












  • $begingroup$
    ohh that makes sense. thanks a lot :)
    $endgroup$
    – Lelouche Lamperouge
    12 hours ago












  • $begingroup$
    Where this pseudo-force comes from?
    $endgroup$
    – Eli
    9 hours ago










  • $begingroup$
    @Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
    $endgroup$
    – Farcher
    9 hours ago


















  • $begingroup$
    ohh that makes sense. thanks a lot :)
    $endgroup$
    – Lelouche Lamperouge
    12 hours ago












  • $begingroup$
    Where this pseudo-force comes from?
    $endgroup$
    – Eli
    9 hours ago










  • $begingroup$
    @Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
    $endgroup$
    – Farcher
    9 hours ago
















$begingroup$
ohh that makes sense. thanks a lot :)
$endgroup$
– Lelouche Lamperouge
12 hours ago






$begingroup$
ohh that makes sense. thanks a lot :)
$endgroup$
– Lelouche Lamperouge
12 hours ago














$begingroup$
Where this pseudo-force comes from?
$endgroup$
– Eli
9 hours ago




$begingroup$
Where this pseudo-force comes from?
$endgroup$
– Eli
9 hours ago












$begingroup$
@Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
$endgroup$
– Farcher
9 hours ago




$begingroup$
@Eli It is introduced so that Newton’s laws of motion can be used in a non-inertial frame of reference. It has no origin other than to make Newton’s laws work.
$endgroup$
– Farcher
9 hours ago










Lelouche Lamperouge is a new contributor. Be nice, and check out our Code of Conduct.










draft saved

draft discarded


















Lelouche Lamperouge is a new contributor. Be nice, and check out our Code of Conduct.













Lelouche Lamperouge is a new contributor. Be nice, and check out our Code of Conduct.












Lelouche Lamperouge is a new contributor. Be nice, and check out our Code of Conduct.
















Thanks for contributing an answer to Physics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f466039%2fis-angular-momentum-conserved-in-impure-rolling%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Plaza Victoria

Puebla de Zaragoza

Musa