1 gal is shorthand for an acceleration of 1 cm/s^2.
A whole lot of people are learning that they should have taken at least one physics course. It might have helped them understand the real world.
I took a couple of semesters of University physics - where you derive the problem instead of plug and chug an equation - and never heard of a “gal”.
Must be the mech. eng. folks that use the term.
Hey, you’d be in trouble too if you had 500 gals shaking you! That must be a good thirty five tons of vibrating flesh.
http://www.youtube.com/watch?v=xzglQ3T9ZJk