Vibration
Because all the objects have a natural frequency
No. There is a frequency range in which people can hear. Very high frequency or low frequency sounds are inaudible to us, but can be heard by some other creatures, like dogs for example.
12hz -20000 hz.
Higher frequencies produce the perception of higher pitch sound. A woman's voice generally contains sounds with higher frequencies than a man's voice contains. An infant's voice contains higher frequencies than an adult's voice does.
Sounds in this range are known as ultrasound. They have frequencies from about 20 kHz to a few GHz. Even the sounds at the low-frequency end are beyond the ability of most people to hear.
effect of high frequency sounds
I assume you mean the frequency at which the head moves back and forth. If this happens only at a certain frequency, then it sounds as if that is caused by resonance - which happens when the excitation (in this case, the head moving back and forth) has a similar frequency to the object's (the printer's) natural frequency.
The answer is essentially in the question. Sound is the sensation caused by vibrations in the air. The faster the vibrations, the higher the frequency. So, when an engine is revved, the frequency of the vibrations it creates increases, and it gives higher frequency sounds, perceived as an increase in pitch.
The frequencies of sounds that can be heard by most people are between 20 and 20,000 Hz. Sounds outside of this range are possible, but can no longer be heard by humans.
Sounds below human's lowest audible frequency of 20Hz are known as Infrasound.
thunderstorm
all different sounds