That's the key to the satisfying "crack" sound of a whip. The tip of the whip accelerates throughout its travel due to a phenomenon called the whip effect.
Here's how it works:
- The user flicks their wrist, creating a wave that travels down the length of the whip.
- As the wave reaches the thicker handle, it encounters more mass and slows down.
- According to the law of conservation of energy, the total amount of energy in the wave needs to stay constant. So, as the wave slows down in the thicker section, the energy gets concentrated in the thinner tip.
- This concentration of energy causes the tip to rapidly accelerate, reaching speeds that can exceed the speed of sound.
- When the tip overcomes the air resistance barrier, it creates a small sonic boom, which is the sharp "crack" sound we hear.