Answer;
Uniformitarianism
Explanation;
-Uniformitarianism is the principle suggesting that Earth's geologic processes acted in the same manner and with essentially the same intensity in the past as they do in the present and that such uniformity is sufficient to account for all geologic change. For example, at an active volcano we can observe lava cooling to form layers of basalt.
James Hutton suggested that deep soil profiles were formed by the weathering of bedrock over thousands of years. He also suggested that supernatural theories were not needed to explain the geologic history of the Earth.
The first thing you should know for this case is that density is defined as the quotient between mass and volume:
D = M / V
In addition, you should keep in mind the following conversion:
1Kg = 1000g
Substituting the values we have:
D = (23.0 * 1000) / (2920) = 7.88 g / cm ^ 3
answer
the density of the iron plate is 7.88 g / cm ^ 3
Actually it's

and it says that the energy of an object (E) is equal to the mass (m) of the object multiplied with the squared speed of light (

). This theory says that mass can be turned into energy and energy can be turned into mass. This is one of Einstein's theory of relativity.
Answer:
it is to do with the static electricity produced by using the comb
The ideal concept for solving this question is based on the Doppler effect, for which it is indicated that the source's listening frequency changes as the distance and the relative speed between the receiver and the transmitter are also changed. However, if the relative velocity between the two objects is zero as in the particular case presented (since both travel at 75km / h) we have that there will be no change in frequency.
Therefore the frequency that I hear and that my sister would listen would be the same.