(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

the gravitational force exerted on a body of mass m by the earth is GmM / r^{2}

1. Express the speed of an artificial satellite which carries out uniform circular motion at height R from the surface of the earth in terms of g and R

2. express the mechanical energy of the artificial satellite of (1) in terms of g, m, and R, where m is the mass of the artificial satellite and the potential energy is assumed to be zero when the distance r is infinite.

2. Relevant equations

Em = Ep + Ek

3. The attempt at a solution

1. done [ans : v =√(gR/2) ]

2.

Em = Ep + Ek = 0 + 1/2 mv^{2}= 1/2 m (gR/2) = mgR / 4

but the answer is - mgR / 4. Why is there negative sign?

thanks

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# Homework Help: Mechanical energy of satellite

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