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Cool goIITian

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16 Nov 2009 17:41:23 IST

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The radius of the earth contracts to half of it's present value .Then the length of the day will be

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The radius of the earth contracts to half of it's present value .Then the length of the day will be

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sankar

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Joined: 28 Jun 2009

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16 Nov 2009 17:42:16 IST

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6 hrs

Rajendra Patil

Cool goIITian

Joined: 2 Oct 2007

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16 Nov 2009 17:52:41 IST

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How 6 hrs please explain

sankar

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16 Nov 2009 19:40:27 IST

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Apply conservation of momentum to solve this.Moment of inertia of earth = = (2mr^2)/5 Initial angular momentum = (2mw r^2)/5 Now if radius contracts to half of its present value (assuming mass of the rearth does not change) Final angualar momentum = L2 = = 2 M (R/2)^2 w2 / 5 = Applying conservation of angular momentum we have L1 = L2 or M R2 w1 / 5 = M R2 w2 / 10 or w2 =2 w1 w1/w2 =T2/T1 (RATIO OF TIME PERIODS)angular vel is doubled thus lengthof the day is halved that is 12/ 2 = 6hrs

sankar

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16 Nov 2009 19:41:35 IST

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