Answer:
1 because I looked it up for sure
 
        
             
        
        
        
The balloon was 30.65 meters above ground.
ANSWER: A
        
                    
             
        
        
        
Answer:
4.06 Hz
Explanation:
For simple harmonic motion, frequency is given by
 where k is spring constant and m is the mass of the object.
 where k is spring constant and m is the mass of the object.
Substituting 0.2 Kg for mass and 130 N/m for k then

 
        
             
        
        
        
I do not agree with the statement.
The "substance" can be a compound.  It's "pure" 
as long as there's nothing else in it but its name.
'Pure' water is 100% H₂O with nothing else in it.
'Pure' table salt is 100% NaCl with nothing else in it.
'Pure' carbon dioxide is 100% CO₂ with nothing else in it.
These example substances are all compounds, not elements.