Answer:
A. nuclear fusion reactions
C. it's still hot from the big bang
Explanation:
The inside of the earth is hot due to some reasons. This heat provides the internal energy the drives processes within the earth interior. Here are some of the ways in which the heat has accumulated: 
- Nuclear reactions within the earth interior by fusion and other radioactive processes releases a large amount of heat. 
- Some heat accreted during the early formation of the earth and has not been lost till this day. 
- Heating due to friction 
These are some of the sources of the earth's internal heat. 
 
        
             
        
        
        
Answer:
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion. Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
Explanation:
 
        
             
        
        
        
Answer:
18m/s^2
Explanation:
Vf = Vi + at
t = distance/ average velocity
(120 + 0)/2 = 60 (average velocity)
400m/60m/s = 20/3 s
insert into first equation:
120 = 0 + a(20/3)
360 = 20a
18 = a
HOPE THIS HELPS!!!
 
        
                    
             
        
        
        
C a meter stick with only centimeters
D a ruler with millimeters and centimeters 
D would be to the nearest half milimeter. Take some time to measure with a 2 inch ruler. Would you really need to know the length to half a mil ?