Well 200 doubled or (x2)=400 if that’s what it means
Answer:
0.625m
Explanation:
Now Velocity of a wave ,V = frequency × wavelength
Wavelength =velocity /frequency
=500/800 =0.625m
Answer: Satellite X has a greater period and a slower tangential speed than Satellite Y
Explanation:
According to Kepler’s Third Law of Planetary motion “The square of the orbital period of a planet is proportional to the cube of the semi-major axis (size) of its orbit”.
(1)
Where;
is the Gravitational Constant
is the mass of the Earth
is the semimajor axis of the orbit each satellite describes around Earth (assuming it is a circular orbit, the semimajor axis is equal to the radius of the orbit)
So for satellite X, the orbital period
is:
(2)
Where 
(3)
(4)
For satellite Y, the orbital period
is:
(5)
Where 
(6)
(7)
This means 
Now let's calculate the tangential speed for both satellites:
<u>For Satellite X:</u>
(8)
(9)
<u>For Satellite Y:</u>
(10)
(11)
This means 
Therefore:
Satellite X has a greater period and a slower tangential speed than Satellite Y
Hydrogen has one proton whereas helium has two protons in its nucleus.
<h3>How hydrogen and helium atoms different from one another?</h3>
Atoms of hydrogen have a single proton in their nucleus and a single electron in the lowest energy level while on the other hand, Helium atoms have two protons in the nucleus and two electrons in the lowest energy level. In this way, we can say that the atomic number of hydrogen is 1 whereas the atomic number of helium is 2 because of the presence of two protons. Hydrogen atom has no neutron while on the other hand, the helium atom has one neutron in its nucleus.
So we can conclude that Hydrogen has one proton whereas helium has two protons in its nucleus.
Learn more about atom here: brainly.com/question/6258301
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Heat
You can usually warm something by adding energy. The added energy can be from light, electricity, friction, a chemical reaction, nuclear reaction, or any other kind of energy. When first added to a substance, energy might be concentrated in one atom, but this one will soon bump into others and spread the energy. Eventually, every atom or molecule in the substance will move a bit faster. When the added energy is spread throughout a substance, it is then called heat energy, thermal energy, or, simply heat. All three terms mean the same thing. Heat is a form of energy, so it has the units of energy. In the SI system, this is Joules. Many other units to measure thermal energy are in common use. Calories and BTU's are common heat units.
Temperature
You cannot measure heat directly, but you can detect its effect on a substance. Changes in heat can usually be detected as changes in temperature. Usually, when you add energy to a bunch of atoms they move faster and get hotter. Similarly, if you remove energy from a bunch of atoms, they usually move less and get cooler.