Summary Damping and resonance

damping Resonance

• The dying away of the amplitude of an • periodic force
oscillatory system due to resistive forces • frequency of driving force = natural frequency
• amplitude decreases over time. • Amplitude of oscillation becomes large
• damping causes energy dissipation • Damping lowers the resonance peak
• energy loss to surroundings
• critical damping occurs when resistive Examples:
forces become large enough to prevent
oscillations occurring. • swing
↳ when a person pushes a child on a
Examples: swing they naturally time the pushes
• musical instruments to match swings natural frequency.
↳ damping controls sound duration Person pushing = driving force. Overtime
• Buildings the child swings higher due to resonance.
↳ damping controls vibrations Amplitude increases up until max,
in buildings particularly due to high natural frequency = driving frequency.
winds. Damping systems are
used to reduce amplitude of vibrations Resonance can be good and bad
and prevent damage.
Bad: Bridge vibrations
→ strong winds or vibrations that match
the natural frequency of the bridge can
lead to resonance and potential damage if
bridge collapses.
Good: swing example.