If you stand up in a big room and echo, your voice will echo
from the walls. As long as the room is empty. Since
the speed of sound is constant, depending on air density, the more humid the
air the faster and farther sound travels. The
speed of sound is constant, you could measure the time it takes for your voice
to echo off the walls. The same thing happens with Doppler radar, but it’s not voice,
it has higher frequency signals.<span> </span>
Answer:
Explanation:
As we know by the principle of uncertainty that the product of uncertainty in position and uncertainty in momentum is given as
so here we know that
so we have
the answer of this question is helium
<span>Variations in Earth-Sun orbital relationships.</span>
Before Pluto was discovered, it was predicted. Astronomers had observed that massive objects can affect the orbits of its neighbors, and, after seeing deviations in the orbits of Uranus and Neptune, assumed something substantial existed beyond their orbits.
When Pluto was spotted, it was thought to be the predicted object and was identified as a ninth planet.
A few decades later, astronomers started discovering more and more objects around other stars and didn’t know whether to call them planets or not. There appeared to be a need to define what a planet means, and that led to what some people consider Pluto’s demotion to a dwarf planet.
The International Astronomical Union decided that full-sized planets must orbit the sun, have a round shape, and have cleared their orbits of other objects. Pluto fulfills the first two criteria, but not the third.
It still goes around the sun, it’s round enough, it’s got moons, and behaves like a planet, but the idea is that Pluto did not form the same way as the rest of the planets. Pluto’s orbit is both eccentric and inclined more than the rest of the planets by about 17 degrees. That’s suggests something is different about this object.
This debate about whether to call it a planet or not is silly, because it doesn’t matter to Pluto what you call it. It is an interesting object, goes around the sun, and shows geology and an atmosphere.
There’s a tendency to define objects based on what they are now, but nothing is constant in the universe. There are some issues with the nomenclature, and a definition today may not apply to the same object tomorrow.
