A 0.002 kg bullet made of lead is fired from a rifle at a speed of 1000 m/s. It hits a block of wood and is slowed to a stop. If all of the energy is absorbed by the bullet and the specific heat capacity for lead is 120 J/kg°C, what is the change in temperature of the lead?

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 =