I need help on science (plz don't give helpless answer)

Astring vibrates with a frequency of 10 hz. why can't a person hear the sound waves produced by the vibrating string, no matter how large the amplitude of the waves? out! this is homework and due tomorrow! you so much!

What is the chemical formula for the compound formed between sodium and flour one

Some molecular compounds, such as hcl, ionize completely in solution. for molecular compounds such as h2co3, most molecules do not ionize in solution. which describes the properties of these two solutes? a. hcl and h2co3 have the same effect on the properties of the solution. b. hcl raises the freezing point of water more than h2co3 does. c. hcl raises the boiling point of water more than h2co3 does.