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an object is stationary in space and located at a distacen 10000km from the centre of a...

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xdsmith | eNoter

Posted March 28, 2013 at 7:24 AM via web

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an object is stationary in space and located at a distacen 10000km from the centre of a certain planet. it is found that 1.0MJ of work needs to be done to move the object to a stationary object point 20000km from the centre of the planet. Caluculate how much more work needs to be done to move the object to a stationary point 80000km from the centre of the planet

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pramodpandey | College Teacher | Valedictorian

Posted March 28, 2013 at 7:47 AM (Answer #1)

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We know ,

W=F.S  ( F- Newton , S meter , W Joules)

W=mgS  ,where g acceleration due to gravity of the planet.

m mass of the object ,s is displacement.

It is given

`1.0 MJ=mg 2.0xx10^7 `     (i)

{20000 km=20000000 m }

`mg=1.0/(2.0xx10^7)`

let W be the work done  if object move 80000 from centre of the planet.

80000 km=80000000 m

`W=(1.0/(2.0xx10^7))xx8.0xx10^7`

`W=4.0 MJ`

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