Simple harmonic motion is the another name for oscillation. Consider oscillating simple pendulum. Here the energy alternates between potential and kinetic. Hence the pendulum oscillates until it is damped by air resistance. Oscillations give rise to many kind of waves in physics.
1. Oscillating water particles give rise to mechanical water waves2. Vibrating air molecules is the cause of sound waves.3. A loop of wire oscillates in a magnetic field and produces electric waves(alternating current).4. Oscillating charged particles emit electromagnetic waves.
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