Gravit. rotational energy related to KE

katewhitney
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"Consider a system of just two particles, with identical masses, orbiting in circles about their center of mass. SHow that the gravitational potential energy of this system is -2 times the total kinetic energy.

Homework Equations


KE = 1/2 mv^2
U(potential) = -2U(kinetic)
grav. potential =
U=-GMm-r

The Attempt at a Solution


we're supposed to set 1/2mv^2 to the rotational gravitational energy -- but I think i have the wrong equation and I don't know where to go from here...
 
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Welcome to PF!

katewhitney said:
"Consider a system of just two particles, with identical masses, orbiting in circles about their center of mass. SHow that the gravitational potential energy of this system is -2 times the total kinetic energy.

Hi kate! Welcome to PF! :smile:

Hint: find the force on each particle, and balance it with the centripetal acceleration to find v. :wink:
 
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