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1. ### Lienard-Wiechert potential for 2 discrete Qs

I've tried a simple derivation of the Lienard-Wiecher potential for 2 discrete charges seperated by dr, but end up with a result which isn't the same as the theoretically correct version: Take two charges q1 @r1, q2 @r2 with r1 > r2, dr = r1 - r2, parallel and both travelling at velocity v...
2. ### Centre of Mass Theorem false for a rotating body?

For a distributed mass, F = M dv/dt where F is the total external force, M the total mass, and v the velocity of the centre of mass. But take the case of a gyroscope, where the force acting on the centre of mass is gravity, assuming it is uniform over the body. The gyroscope doesn't topple...
3. ### Some questions on rigid modies in Landau's Mechanics book

The following comes from Landau's Mechanics, pages 97 - 98. For a particle in a rigid body, v = V + W x r -- (1) where for some origin O of the moving body measured in the "fixed" system of co-ordinates, v = particle's velocity in the "fixed" system, V = velocity of O in "fixed" system...
4. ### Question concerning rigid bodies

The following comes from Landau's Mechanics, pages 97 - 98. For a particle in a rigid body, v = V + W x r -- (1) where for some origin O of the moving body measured in the "fixed" system of co-ordinates, v = particle's velocity in body in the "fixed" system, V = velocity of O in "fixed"...