For 10 points, name this quantity that is defined with respect to the International Prototype Kilogram.
The oscillation frequency of a piezoelectric crystal changes linearly with a change in this quantity according to the Sauerbrey equation, which is superseded by the Z-match method when the change in this quantity is large. A device invented by Brian Kibble whose name suggests that it measures this quantity calculates it from the current and voltage in a wire, obtaining in the process a very accurate value for Planck's constant. An apparent change in this quantity is used to measure magnetic susceptibility in a device named for Louis Georges Gouy ("lwee george gooey"). The weak equivalence principle posits the indistinguishability of the inertial and gravitational types of this quantity, whose SI unit is defined by a platinum-iridium cylinder stored in a vault in Saint-Cloud ("san-KLOO"), France. For 10 points, name this quantity that is defined with respect to the International Prototype Kilogram.
The oscillation frequency of a piezoelectric crystal changes linearly with a change in this quantity according to the Sauerbrey equation, which is superseded by the Z-match method when the change in this quantity is large.
mass &lt;Physics&gt; Bonuses