Abox rests on the (frictionless) bed of a truck. the truck

driver starts the truck and accelerates forward. the box!

immediately starts to slide toward the rear of the truck

bed. discuss the motion of the box, in terms of newton's

laws, as seen (a) by mary standing on the ground beside

the truck, and (b) by chris who is riding on the truck

(fig. 4–35).

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 =