tusenfem

For answers about ‘c’ see:
http://www.physicsforums.com/showthr...highlight=mass

For the relationship between mass and force see:
http://www.physicsforums.com/showthr...highlight=mass

For details about Einstein’s thoughts on c squared see the biography of Einstein by his lifelong working colleague and friend; I have mislaid my copy so cannot quote the details.

For a different structural equation that does not include mass see my latest addition which will be on line in about two hours from now.