Answer:
- Particles smaller than atoms are called subatomic particles .
- There are three famous subatomic particles, proton, neutron and electron .
- The study of sub atomic particles are called particle physics
- These particles can be divided as Brayons and Leptons
- These particles are often held together by one of the four fundamental particles ( Weak force, strong force, electromagnetic force, gravitational force).
They are similar because they are all colors in the spectrum and they are different because you cant seperate primary colors but you can seperate secondary
Answer:
For the first situation, we first need to find the mass of the second train car.
In order to do that, we apply the conservation of the amount of movement:

and we have as a result:
m2 = 289.6875
For the second situation, also we will apply the conservation of the amount of movement:

and we have as a result:
V = 2.64 (it is moving to the right)
Answer:
Motors commonly contain a "commutator" which allows a magnetic field due to a loop of wire to always be in a say "clockwise or counterclockwise" direction even tho the loop of wire is rotating.
That means that magnetic field due to the surrounding magnets is always in the same direction, but the magnetic field due to the rotating loop of wire is continually changing so that it will always oppose the surrounding field which remains in a constant direction.
This is most easily seen in a "DC - direct current motor".