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24 Oct 2011 16:08:58 IST

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circilar motion

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when an object moves around a circular path with constant speed what is the effect on its Kinetic Energy ? (Constant or Variable)why ?

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babujee

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24 Oct 2011 17:00:35 IST

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dont know

Sagar Saxena

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24 Oct 2011 23:31:07 IST

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kinetic energy of object is constant

if speed, redius and mass all are constant.

Anjali Singh

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25 Oct 2011 16:12:47 IST

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but the formula for kinetic energy is half MV square.where V = velocityand in circular motion , velocity is variable due to change in the direction of motion. so Won't K.E. be variable ?

shishir kumar

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25 Oct 2011 16:29:16 IST

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in the K.E. formula i think v sqaure is the dot product of velocity vector.......and dot product=product of magnitude of velocity multiplied by cos thita.........so i think 2 velocity vector must substend equal angle between equal time intervals and this happens when speed is constant........but i m not sure about this answer

Anjali Singh

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25 Oct 2011 17:04:02 IST

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i don't think speed has got anything to do with thita...because speed is a scalar quantity...its velocity which can be broken into components. what say ?

asdfghjkl

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25 Oct 2011 19:43:19 IST

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heyya lets take this analogy ...... electrons revolve around the nucleus of an atom n we generate electricity to do work from the kinetic energy of these atoms .....according to work energy theorem "work done = change in potential/kinetic energy" in this case potential energy is constant (as distance from nucleus is constant) but still work is being done which means kinetic energy changes so it is a variable

Anjali Singh

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26 Oct 2011 12:55:19 IST

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so that means that the answer to my question is = vAriable K.E. ?

asdfghjkl

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26 Oct 2011 17:52:28 IST

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yup it means variable ke

hemang

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26 Oct 2011 18:58:03 IST

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is the motion on a vertical circle or a horizontal circle?

if the former then it is constant for uniform circular motion.

if the latter then damn sure variable ( since it is non uniform).

manish singh

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27 Oct 2011 13:15:08 IST

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@anjali: shishir was right.listen,velocity is a vector but energy is not. because energy does not depend on direction analogue. That is why kinetic energy doesn't have to do anything with direction and its not changing! So K.E. is constant!

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