Impedance is force divided by velocity and measures a body’s response to force.

Evidence

Roughly speaking, impedance, which we symbolize with the letter Z, measures the response of a body to a force—in fact, the force applied divided by the velocity attained (Z ~ force ÷ velocity). A heavy object moves slower than a light one after the same force is applied starting at rest, so impedance is high for a heavy object, low for a light one. This is still a rough definition, since in the measurement of Z, the force is taken to vary sinusoidally (see chapter 3), and the velocity, while also sinusoidal, may lag or lead the force. — Eric J. Heller, Why You Hear What You Hear- An…, 65

Categorization

• DEFINE: Defines mechanical impedance as the ratio of applied force to attained velocity, the core concept the chapter builds on.