0
$\begingroup$

When an object moves in a circle it experiences centripetal force directed towards centre, But when we place an object on a disk which is rotating why does the object moves away from centre instead of moving towards the centre.

| cite | improve this question | | | | |
New contributor
Ramsay is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
$\endgroup$
  • $\begingroup$ Is there any force acting towards the centre (on an object on a rotating disk) which could cause it to move in that direction? $\endgroup$ – Feynman's Cat 2 days ago
  • 1
    $\begingroup$ A force is required on the obj. to move in a circle $\endgroup$ – Joe Santino 2 days ago
0
$\begingroup$

Short answer: It is because the centripetal force does not act on the body.

Consider the situation like this. Let us assume that the body is placed on a frictionless groove on a circular disc. Now, if you start rotating the disc, the particle does not feel any centripetal force. Now, consider a point just before our object under consideration.(towards the centre that is).

Since you had given the disc an angular velocity, the next instant, because of the centripetal force, the point before the body goes inward, while the body does not. A good way to imagine it would be like this. It is not the object that is falling away, but rather all the points on the disc are going inward because of the centripetal force, while the object, without centripetal force does not move along with them.

This means that the particles will separate, not because the body is moving out of the disc, but because the points on the grove are moving towards the centre, away from the body

An ultra-simplified version of the situation can be seen in the image below

enter image description here

Note that the ball does not experience any force towards the centre, the normal force pushes the body to the left, but not towards the centre.

| cite | improve this answer | | | | |
$\endgroup$
  • $\begingroup$ Thank you . I was really stuck on this! $\endgroup$ – Ramsay 14 hours ago
0
$\begingroup$

It is not necessary,It is only possible if the frictional coefficient has value less than necessary to provide for the centripetal force, In the case you mentioned the friction coeff. is less thus the object can't have enough centripetal acc. to satisfy the circular locus the disc's periphery undertakes.

| cite | improve this answer | | | | |
$\endgroup$

Your Answer

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

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.