- #1
RandomMystery
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I have two physics books that state that
U(r) = -GMm/r
What I don't understand,is how can potential energy be negative?
I've done the integral of GMm/r^2 from infinity to r, but I don't quite get the concept of negative potential energy.
I don't understand why using r=infinity as the initial potential energy and as the initial reference point, always makes U negative from that perspective.
For example
E = U + K
E = -GMm/r + [mv^2]/2
I don't understand this infinity perspective system, so instead I use a mass or Earth perspective:
U= GmM/(r+x) + [4piGmpr^2]/6
*[4piGmpr^2]/6 is the integral of 4piGmpr/2 which is an estimation of the force acting on a particle inside Earth.
Here U is always positive. I'm having trouble understanding the value of U from the "infinity" perspective.
U(r) = -GMm/r
What I don't understand,is how can potential energy be negative?
I've done the integral of GMm/r^2 from infinity to r, but I don't quite get the concept of negative potential energy.
I don't understand why using r=infinity as the initial potential energy and as the initial reference point, always makes U negative from that perspective.
For example
E = U + K
E = -GMm/r + [mv^2]/2
I don't understand this infinity perspective system, so instead I use a mass or Earth perspective:
U= GmM/(r+x) + [4piGmpr^2]/6
*[4piGmpr^2]/6 is the integral of 4piGmpr/2 which is an estimation of the force acting on a particle inside Earth.
Here U is always positive. I'm having trouble understanding the value of U from the "infinity" perspective.
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