<h2>Answer: decibels
</h2>
The decibel 
is the relation between two values: the pressure produced by a sound wave and a pressure taken as a reference. Resulting in a dimensionless value.
It should be noted that itself<u> is not a unit of measure</u>, since in reality the unit is bel 
(which <u>is not part of the International System of Units</u>) in honor of Alexander Graham Bell.
However, given the amplitude of the measured elements in practice, its submultiple, the decibel, is used. That is, this quotient is a logarithmic expression, where 
<h3>
Answer: True</h3>
For example, a very dense metal will sink to the bottom while something like wood will float on the surface. The wood is less dense compared to the water, which is why it floats. Density is the measure of how much stuff you can pack in a certain volume. The higher the density, the more stuff per volume. Think of it like packing a suitcase. If there's barely anything in there, then we can say its density is low. The more stuff crammed in the suitcase will increase the density (and therefore the weight), while keeping the volume the same.
Yes, Sliding friction opposes the movement of the book, slowing it down.sliding That's the 'kinetic' kind.. According to Newton's second law, F=ma. That is, the bear's acceleration should be proportional to the total force acting on the bear. As the bear's velocity is constant, its acceleration is zero. Therefore, the total Force acting on the bear is zero. Thus, the friction has to be equal in magnitude and opposite in direction to the bear's weight. As W=mg, we get that its weight is <span>9.8*400=3,920 Newton. Thus, the friction acting on the bear is 3,920 Newton</span>
Answer:
In the air
Explanation:
There are three states of matter:
- Solids: in solids, the particles are tightly bond together by strong intermolecular forces, so they cannot move freely - they can only vibrate around their fixed position
- Liquids: in liquids, particles are more free to move, however there are still some intermolecular forces keeping them close to each other
- Gases: in gases, particles are completely free to move, as the intermolecular forces between them are negligible
For this reason, it is generally easier to compress/expand the volume of a gas with respect to the volume of a liquid.
In this problem, we are comparing water (which is a liquid) with air (which is a gas). From what we said above, this means that the change in volume is larger in the air rather than in the water.
I would look this one up on Google
