negative work done by the gravitational force in bringing the point from infinity to that point,
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更新1:
(-GMm/r^2).dr how do you explain this? in geometry, i think this is positive as they are in the same direction (the dot product of two vectors)
更新2:
however in physics i know this is negative as there is an external force to keep the KE of the body constant. so gravity does negative work in bringing the body to that point i am confused at the beginning - defining the sign of dW