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.
Mass. 1  Mass is a measure of the amount of matter an object contains. - 2  The amount of mass in an object does not change. - 3  Gravitational force can change (i.e. the moon), which can cause weight to change. - 4  This is the reason scientists prefer to measure matter by its mass rather than its weight.