You are sitting on a deck of your house surrounded by oak trees. you hear the sound of an acorn hitting the deck. you wonder if an acorn will do much damage if instead of the deck it hits your head. let the mass of the acorn be 3.3 g. suppose it drops from a height of 12 m (relative to your head). assume that the acorn sinks in 0.50 cm of your head skin before coming to a stop.
1) determine the magnitude of the force that the acorn would exert on the head.

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

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 =