Normal mode

Definition

A normal mode is a pattern of motion in which all parts of a system oscillate with the same frequency and in a fixed phase relation. In mechanical systems, these modes are often standing waves.

5 Must Know Facts For Your Next Test

1. Normal modes occur at specific frequencies known as natural frequencies.
2. In a normal mode, every point on the object moves sinusoidally with the same frequency.
3. The number of nodes (points that remain stationary) increases with higher-order normal modes.
4. Energy in a normal mode is equally distributed among all parts of the system oscillating.
5. Normal modes can be visualized using techniques such as Chladni patterns for vibrating plates.

Review Questions

• What is the relationship between normal modes and natural frequencies?
• How does the number of nodes change with higher-order normal modes?
• Explain how energy distribution occurs in a system oscillating in its normal mode.

Related terms

Standing Wave: A wave that remains stationary within a medium, characterized by points of no displacement called nodes and points of maximum displacement called antinodes.

Resonance: A condition where an external force drives a system at its natural frequency, resulting in large amplitude oscillations.

Natural Frequency: The frequency at which a system naturally oscillates when not subjected to external forces other than its own restoring force.