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.
The definition of inert is slow or having no action or power to move. An example of inert is a slug that is standing still. having inertia; without power to move, act, or resist. tending to be physically or mentally inactive; dull; slow.
The quantity of matter in a body. The inertial mass is the mass as a measure of resistance of a body to changes in its motion, and the gravitational mass is the mass as a measure of the attraction of one body to another. The general theory of relativity shows inertial and gravitational mass are equivalent. By a suitable choice of units they can be made numerically equal for a given body, which has been confirmed to a high degree of precision by experiment. Mass is always conserved.