Damping

Meaning: Damping is the loss of mechanical energy from an oscillating system, usually as thermal energy through friction, air drag or viscous resistance. Each cycle removes some energy, so amplitude shrinks, often exponentially. Underdamped systems oscillate with decaying amplitude; critically damped systems return to equilibrium fastest without overshooting; overdamped systems return slowly without oscillating.

Equation: Fdamp = −bv, where Fdamp is the resistive force (N), b is the damping coefficient (kg/s), and v is velocity (m/s); the minus sign shows the force opposes motion.

On the MCAT: A passage describes a pendulum, spring-mass system or fading sound and asks what happens to amplitude, energy or period. Amplitude and total mechanical energy decrease, while for light damping the period and frequency change very little. In resonance graphs, more damping lowers and broadens the peak. Shock absorbers approximate critical damping.

Common confusion: Students assume a fading sound or swing must slow down or drop in pitch. With light damping, the frequency is nearly unchanged; the amplitude (and so the intensity) falls. The energy is not destroyed; it is converted to thermal energy.