Answer: False but read why
Heated water molecules expands ( become less dense) but they do float to the top.
Answer:
Static friction
Explanation:
When there is contact between two surfaces and there is no movement, there is static friction. So, if we have a book that rests on a wooden table, we have an example of Static friction, where this force avoids the movement of the book.
2Mg + 2HCl →2MgCl + 2H₂
Balanced is:
4Mg + 4HCl → 4MgCl + 2H₂
I Hope I Helped
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The frequency of the human ear canal is 2.92 kHz.
Explanation:
As the ear canal is like a tube with open at one end, the wavelength of sound passing through this tube will propagate 4 times its length of the tube. So wavelength of the sound wave will be equal to four times the length of the tube. Then the frequency can be easily determined by finding the ratio of velocity of sound to wavelength. As the velocity of sound is given as 339 m/s, then the wavelength of the sound wave propagating through the ear canal is
Wavelength=4*Length of the ear canal
As length of the ear canal is given as 2.9 cm, it should be converted into meter as follows:

Then the frequency is determined as
f=c/λ=339/0.116=2922 Hz=2.92 kHz.
So, the frequency of the human ear canal is 2.92 kHz.