Answer:
He made great advancements in developing a logical way to know more about the universe and celestial entities inside the space. And this theory is termed to be heliocentric in nature.
Explanation:
- In early times most of the people believed that our planet Earth is the center of the universe or the solar system and rest of the celestial entities move around it in a given path, so, it confused the well known scientist named as Galileo Galilei. As, he observed the different dark patches or shadow like textures on the face of the Sun.
 
- While, it is more obvious to known that any object having multiple small shadows means that it is present inside such a region that all of the celestial entities move or orbit around it in a given way.So, he concluded that planet Earth itself move around the red Giant in a given way rather then being the center of the universe.
 
 
        
             
        
        
        
Answer:
1). 
2). Toward us
3). 
4). Toward us
5). 
6).  Away from us
7). 
8). Away from us
Explanation:
Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when it is moving away from the observer (that is known as the Doppler effect).
The wavelength at rest is 121.6 nm (
)

 
Then, for this particular case it is gotten:
Star 1: 
Star 2: 
 
Star 3: 
 
Star 4: 
 
Star 1:
 
Toward us
Star 2:
 
Toward us
Star 3:

Away from us
Star 4:

Away from us
Due to that shift the velocity of the star can be determine by means of Doppler velocity. 
  (1) 
Where 
 is the wavelength shift, 
 is the wavelength at rest, v is the velocity of the source and c is the speed of light.
  (2)
<em>Case for star 1 
:</em>
<em></em>
 
 
Notice that the negative velocity means that is approaching to the observer. 
<em>Case for star 2 
:</em>
 
 
<em>Case for star 3 
:</em>
 
 
<em>Case for star 4 
:</em>
 
 
 
        
             
        
        
        
Geometrically, a screw can be viewed as a narrow inclined plane wrapped around a cylinder. Like the other simple machines a screw can amplify force; a small rotational force (torque) on the shaft can exert a large axial force on a load.
 
        
             
        
        
        
Answer:
Powerful electromagnets are fitted on top of guideways either ttract or repel the magents fitted on the bottom of train. The froce of attraction/repulsion rasies the train in hovering position.
Explanation:
Magentic fields exist between two opposite/like poles. The poles do not have to be touching each other. They can be separated by a distance in a medium that doesn' block magnetic field.
In magelv train the magnetic forces between two poles are used to operate the train. The two poles are separated by train body and air.