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Bravodhan
Jul15-11, 11:26 PM
When I multiplied angular accelaration with surface area of sphere .I got an equation for energy.

What do this equation mean by?
Is this equation describe gravitational energy?

Drakkith
Jul16-11, 12:22 AM
Can you post the equations you used and the problem they were used in?

Bravodhan
Jul16-11, 12:54 AM
But dimensionally this equation is correct.

Bravodhan
Jul16-11, 01:04 AM
Angular accelaration*surface area of a sphere = Energy
Angular velocity/time*4(pi)r2=Energy

Dimensional formula:-
M0 L0 T-2 * M L2 T0 = M L2 T-2

M L2 T-2 = Energy

I take this energy equation in terms of planetry motion .

Vanadium 50
Jul16-11, 06:24 AM
The fact that something has dimensions of energy doesn't make it an energy. Torque, for example.

jimgraber
Jul16-11, 08:44 AM
First, if its truly surface area, you get M0 not M. The whole equation is massless.
The way you have written it, it is the mass of a thin spherical shell times the angular acceleration.

Second, Work also has the dimensions of Energy. I think your equation gives you the amount of work expended to accelerate (spin up or spin down) the thin spherical shell by that much.
Best,
Jim Graber