A 5 kg block is pulled across a table by a horizontal force of 40 N with a frictional force of 10N opposing the motion. Determine the acceleration of the object. *

the bal will not change its velocity.

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 =