Answer: No, because the atomic number shown in the symbol (Z = 15) is not the atomic number of oxygen (Z = 8)
Explanation:
When we have an atom, the number in the top left is the mass number A, is equal to the sum between the number of neutrons and protons in the atom.
In this case, between protons and neutrons, we have 32.
The number at the bottom left is the atomic number Z, which is equal to the number of protons in the atom.
Particularly, this number is different for every element. For example, for the oxygen we would have Z = 8, this means that the oxygen has 8 protons.
In the image, we can see Z = 15, then the atom has 15 protons, this means that it can not be oxygen (Z = 15 is for phosphorus, then this atom would be phosphorrs). Then the symbol can not be used, because that is not oxygen.
The correct answer is <span>Montana.
In fact, we see from the table that Montana is the state with the largest amount of coal mined in 2005: 120 billion tons, while all the other states have a smaller amount of coal mined (37, 68 and 78, for West Virginia, Wyoming and Illinois, respectively).</span>
Answer:
M1 = 16.9 mA
M2 = 0 A
Explanation:
As the ratio of the two sets of series resistors is almost exactly identical, there is no voltage difference across M2 to cause current flow
269/(269 + 439) = 0.3799...
500/(500 + 815) = 0.38022
M2 = 0
M1 sees only the current flowing through the far left resistors in series
A = V/R = 12/(269 + 439) = 0.016949... ≈ 16.9 mA
Answer:
Explanation:
In an experimental research, the control group is the group that serves as the neutral group that is not given any form of treatment and serves as the group in which the experimental groups are firstly compared to. Thus, <u>the control group in the question described is the Third group</u>.
While experimental groups are the groups that receive treatments required to make an inference from the experiment. From this description, <u>it can be deduced that the First and the Second group are the experimental groups.</u>
Answer:
See the explanation below
Explanation:
The speed of sound waves can be calculated using the following equation:
![v_{s}=\sqrt{\frac{E}{ro} } \\where:\\E = Young's modulus [GPa]\\ro = density of the material [kg/m^3]](https://tex.z-dn.net/?f=v_%7Bs%7D%3D%5Csqrt%7B%5Cfrac%7BE%7D%7Bro%7D%20%7D%20%5C%5Cwhere%3A%5C%5CE%20%3D%20Young%27s%20modulus%20%5BGPa%5D%5C%5Cro%20%3D%20density%20of%20the%20material%20%5Bkg%2Fm%5E3%5D)
Let's do the exercise of comparing two materials one denser than the other, as is steel and aluminum
ro_steel = 7500 [kg/m^3]
ro_aluminum = 2700 [kg/m^3]
E_steel = 200 [GPa]
E_aluminum = 70 [GPa]
Now replacing the values in the equation for each material.
![v_{steel}=\sqrt{\frac{200*10^9}{7500}}\\ v_{steel}=5163[m/s]](https://tex.z-dn.net/?f=v_%7Bsteel%7D%3D%5Csqrt%7B%5Cfrac%7B200%2A10%5E9%7D%7B7500%7D%7D%5C%5C%20v_%7Bsteel%7D%3D5163%5Bm%2Fs%5D)
And for the aluminum
![v_{aluminum}=\sqrt{\frac{70*10^9}{2700} }\\ v_{aluminum}=5091.75[m/s]](https://tex.z-dn.net/?f=v_%7Baluminum%7D%3D%5Csqrt%7B%5Cfrac%7B70%2A10%5E9%7D%7B2700%7D%20%7D%5C%5C%20v_%7Baluminum%7D%3D5091.75%5Bm%2Fs%5D)
In this way we can see that sound propagates faster in denser materials.
