By doing so, weld current and force is focused into the small area of the projection, and heat is obtained from the resistance to the flow of the welding current. Due to this heat, the projections collapse and the parts are weld together. Another successful welding technique is capacitor discharge stud welding, which uses weld studs or specially formed bolts for welding instead of projections.
Definition of inert. 1  1 : lacking the power to move. 2  2 : very slow to move or act : sluggish. 3  3 : deficient in active properties; especially : lacking a usual or anticipated chemical or biological action.
Inertia is scientific principle and not a property of matter. It is not quantifiable in the way you are suggesting, and it has no units. Inertia is the principle that a body will continue to move in the same way (that is, at the same velocity) unless acted on by a force.he mass of a body determines the momentum P of the body at given velocity v; it is a proportionality factor in the formula: P = mv The factor m is referred to as inertial mass.