I have read that mass can be measured by the degree of movement resistance to surrounding activity, so that an object high in mass will take more energy exertion to move than an object with a relatively lower mass measurement. Does anyone else have a different working definition for the word mass? Does the definition I have for mass not have any validity? If e=mc2 than does this mean that energy is measured by an objects potential to move surrounding fields of substance as well as an objects ability to resist a change in direction of movement once set in motion? Does a car traveling at 60 mph have an easily measured higher degree of mass as a result of the fact that it takes much more energy exertion to alter the position of a car at this speed than a stationary one or is it so that only objects moving at great speeds have a noticeable degree of mass increase?