Mechanical resonance

Mechanical resonance occurs when something vibrates at its natural frequency. This means that when something vibrates at its natural frequency, the vibrations build up and become stronger. Think of a swing. If you push it gently and slowly, it won't make big swings. But if you push it with the same force over and over again at the same speed, it will start to swing higher and higher because its vibrations build up. That is mechanical resonance.