The circular clapper on the air side of a dry pipe sprinkler valve has a diameter of 10 in (25cm). what force will be acting on this clapper due to an air pressure of 40psi(3bar)?
correct answer from back of book is: 3141.6lbs
how do i get this answer? show me all the formulas and steps you took to get this answer,

the area between the graph and the t axis

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =