Explain why simple harmonic motion is called so ?

Explanation

### Step-by-Step Solution:

1. **Definition of Simple Harmonic Motion (SHM)**:
- Simple Harmonic Motion is defined as a type of periodic motion where the restoring force is directly proportional to the displacement from the equilibrium position and acts in the opposite direction.

2. **Representation by Harmonic Functions**:
- The motion in SHM can be mathematically represented by sine or cosine functions. These functions are known as harmonic functions. For example, the displacement can be expressed as:
- \( y = A \sin(\omega t) \)
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