Arm and leg weakness can be caused by a variety of different conditions, some of them temporary and others chronic. Excessive exercise is one cause of temporary fatigue in the major muscle groups, although this is not considered true muscle weakness.
Mass is an intrinsic property of the body and gravity is the force exerted on any body by the things that surround it. Weight, on the other hâ¦and, depends on gravity. It is equal to the product of the mass of the body and the gravitational force acting on it.
Updated July 10, 2016. The difference between density and specific gravity is that specific gravity is an expression of density in relation to the density of a standard or reference (usually water). Also, density has units, while specific gravity is a pure number or dimensionless.