Dimensions

I was taught in university science classes that the dimensions on the left side of an equation should match the dimensions on the right.  I had trouble applying this to Einsteins equation because energy is expressed in so many ways (joules, foot-pounds, kilowatt hours).  I finally figured out that the right way to look at it is energy = force times distance and force = mass times acceleration and acceleration = distance divided by time squared.  Combining these gives energy = mass times distance squared divided by time squared, which, of course, matches the dimensions on the right side of the equation.

My next blog will give an example.