Answer:
An element is a pure substance that cannot be separated into simpler substances by chemical or physical means. There are about 117 elements.
Explanation:
 
        
                    
             
        
        
        
Yes you are right cuz charging by friction cant be done in fluids( liquid and gas)
        
             
        
        
        
Answer:
0.3956
Explanation:
Newton's 2nd law of motion says that Force = Mass*Acceleration (f=ma) so to find the force used on the football you multiply it's mass by its acceleration. 
0.43*0.92 = 0.3956.
0.4 if you round
 
        
             
        
        
        
Answer:
11,890
Explanation:
First we need to know what is considered a significant figure.
A significant figure is a value that is not a zero at the start OR end of a value.
Which means, the 0 in the value of 90 or 0.363 are not considered a significant figure.
The 0 in the value of 3056 is considered a significant figure.
So from the table, we can deduce:
0.275 has 3 significant figures
750 has 2 significant figures

has 3 significant figures.
11,890 has 4 significant figures.
320,050 has 5 significant figures.
So from the above, we can already see the answer.