Expert: James Gort - 12/3/2011

Question
sir why the value of g gets changed when it suddenly stops spinning?and sir by any mean can the value of gravitaional constant "G" can change?

Answer
Hello Shabahat,

An object which is spinning is in an accelerating reference frame. "g" is the "gravitational acceleration", or simply the acceleration due to the mass of the earth (or the moon, etc.). The gravitation acceleration (g) will not change if an object stops spinning, but the measured acceleration WILL change, if you measure it while you're on the spinning object. That's because "centripetal acceleration" due to the rotating reference frame must be added (vectorially) to the "gravitational acceleration" to get the TOTAL acceleration experienced.

No, the gravitational constant G does not change (at least in our lifetime or even the sun's lifetime). There are some theories, however, that it has changed in the distant past.

Prof. James Gort