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.
Answer:
A massive object (like a galaxy cluster) bends the light from an object (like a quasar) that lies behind it.
Explanation:
A massive object, like a galaxy cluster, is able to deform the space-time shape as a consequence of its own gravity, so the light that it is coming from a source that is behind it in the line of sight will be bend or distorts in a way that will be magnified, making small arcs around the cluster with the image of the background object.
This technique is useful for astronomers since they make research of faraway objects (at hight redshift) that otherwise will difficult to detect with a telescope.
<span>Tachyons are studied in an area called particle physics, and I must say this is a bit out of my league, but I'll give you some general thoughts. Tachyons are hypothetical particles resulting from what physicists call a thought experiment. Back in the 1960s, some physicists wondered what would happen if matter could travel faster than the speed of light, something that is supposed to be impossible according to the Theory of Relativity. So these particles may or may not exist because they have not been proven or disproven by real experiment as of yet. What people have done is apply existing formulas to the unique properties of tachyons (like imaginary mass!). What comes out is a particles that go faster when they lose energy with a MINIMUM velocity of the speed of light and a maximum velocity of infinity! Hope that helps Ben, theoretical physics is a weird place and is not too far off from philosophy.</span>
Electromagnetic radiation
The answer is 12.36. hoped this helped!