Fact 1: Hitting an object causes the particles in that object to vibrate.

Fact 2: By it's nature, a vibration is a frequency wave .

Given the two facts above, answer the question "what does hitting an object cause?" with the following options: 
- frequency waves
 - harmful substances
 - Electrical energy
 - chemical reaction
 - friction
 - Movement
 - heat energy
 - chemical changes


 

 frequency waves        