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Cool goIITian

Joined:	19 Apr 2012
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19 Apr 2012 16:31:15 IST

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Can the velocity of centre of mass change even if no work is being done on the system?

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Can the velocity of centre of mass change even if no work is being done on the system?

Comments (4)

Viraat Gupta

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Joined: 21 Jun 2011

Posts: 743

19 Apr 2012 17:21:33 IST

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velocity of centre of mass doesnot change until and unless an external force is applied to it . so i guess the answer would be a no

Shantanu Gontia

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Joined: 19 Apr 2012

Posts: 53

19 Apr 2012 18:05:12 IST

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a book of mine says different ..The explanation given is, When a person acccelerates himself on a rough horizontal surface without any flipping betweeen his shoes and ground work done by friction, normal reaction and weight are all zero but COM changes. I dont get it

kartikAIR1

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Joined: 2 Mar 2012

Posts: 304

19 Apr 2012 18:47:58 IST

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Yes.

considerr a case :

When a rigid Ball rolling in frictionless horizontal surface collides with rigid wall.

Its velocity changes !!!!!

here fprce is applied by rigid wall but POINT OF APPLICATION OF FORCE DOESN't MOVE

hence WORK DONE = F.ds = F*0 = 0

So, the velocity of centre of mass change even if no work is being done on the system

asif

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Joined: 15 Apr 2012

Posts: 104

19 Apr 2012 19:16:52 IST

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in case of uniform circular motion,work done by force is zero.....but dirn.of velocity,is changing,and velocity is vector quantity,so velocity changes even if no work is done.........

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