An 8.0 g bullet is fired from a gun at 120 m/s into a 2.0 kg block of wood sitting on a fence post. if the bullet hits the wood and remains in it, what is the speed of the block after the collision?

Explanation:

As we know that bullet strike the block and fix in it

so here if bullet and box is taken as a system then there is no external force on it

so here the initial momentum of bullet and block must be equal to final momentum of bullet and block

so here we have

now we have

now from above equation we have

the components of a vector are the parts of the vectors that are to each other.

b perpendicular

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 =