To prevent static sparks that could occur while you fill fuel is that, a person who is filling the tank should remember that the nozzle of the fuel pump hose should always be in connected or in contact to the tank. This will prevent static sparks from happening to the boat that is going to be used and prevent harm to the person using or refilling the fuel.
Answer:
P =40.69 atm
Explanation:
We need to find the approximate pressure at a depth of 400 m.
It can be calculated as follows :
P = Patm + ρgh
Put all the values,

So, the approximate pressure is equal to 40.69 atm.
The air resistance on the feather would be the correct answer.
Answer:

Explanation:
In series combination, the equivalent resistance is given by :

Let the identical resistors be R. We have, 
So,

So, the resistance of each resistor is
.