D.
50 mph - 30 mph= 20 mph net velocity 
change. 
20mph/3600 seconds/hour= .00555 MPS
.0055 miles per second
40 seconds to complete the change
.0055/40= .000138
        
             
        
        
        
Doubling the size of a load resistor increases the load current. Increasing the load resistance, in turn the total circuit resistance is reduced. The load current would not be half as much since when you increase the size of load resistor then load current increases.
        
             
        
        
        
Answer:
 Case A 
Explanation:
given,
size of bacteria = 1 mm x 1 mm
velocity = 20 mm/s
size of the swimmer = 1.5 m x 1.5 m
velocity of swimmer = 3 m/s
Viscous force

for the bacteria


for the swimmer


from the above force calculation 
In case B inertial force that represent mass is more than the inertial force in case of bacteria.
Viscous force is dominant in case of bacteria.
So, In Case A viscous force will be dominant.
 
        
             
        
        
        
What are the statements?? I need to know the statements so i can help you.
(You can message me the statements or comment them. I will try and help you as soon as possible :)! )
        
                    
             
        
        
        
The wise and careful use of energy is called CONSERVATION