Answer:
4 m/s
Explanation:
Momentum is defined as:

where
m is the mass of the object
v is its velocity
For the object in this problem, we know:
p = 200 kg m/s is the momentum
m = 50 kg is the mass
Solving for the velocity, we find:

This phenomena is also called the Doppler shift. When the source of light is approaching towards an observer, the color tends to be blue shifted, but when the source is moving away or being stretch, the color tends to red shifted. In astronomy it can be use how fast galaxy is moving towards us or how fast it moves away.
Answer:
send the wagon down a higher hill
Once the atomic number of an atom is known, the number of electrons can be deduced depending on if the atom is an ion or a neutral one.
<h3>Atomic number</h3>
The atomic number of an atom is the number of protons in the nucleus of the atom.
For atoms that are neutral, that is, no net charges, the number of protons is always equal to the number of electrons. In other words, the positive charges always balance the negative charges in neutral atoms.
Thus, if the atomic number of a neutral atom is 6, for example, the proton number will also be 6. Since the proton must balance the electron, the number of electrons will also be 6.
More on atomic numbers can be found here; brainly.com/question/17274608
Answer:
the orbits of the planets are elliptical
the sun is the center of the solar system
includes 9 planets