Their difference lies in the prefix used before each root word, atom. The diatomic molecules are composed only of 2 atoms such as that of the diatomic elements: H2, O2, N2, Cl2, etc. On the other hand, polyatomic molecules are made up of three or mole atoms such as NH4+, H2SO4, etc. 
        
             
        
        
        
A bowler who always left the same 3 pins standing could be considered a C. Precise bowler as from bowling countless number of times he has observed the same amount of pins knocked down each time.
        
             
        
        
        
Answer:
The number of crates is 84580.
Explanation:
mass, m = 30 kg
height, h = 0.9 mm  
Power, P = 0.5 hp = 0.5 x 746 W = 373 W
time, t = 1 minute = 60 s
Let the number of crates is n. 
Power is given by the rate of doing work. 

 
        
             
        
        
        
The energy added here is potential energy since it is moving upward 180 meters in a gravitational field.  This is then turned into KE when it rolls down.  2524N x 180m = 454,320J