Keiko is riding a skateboard 2 m/s, west. how long will it take her to reach a velocity of 8 m/s, west if her acceleration is 2 m/s2

Answer : The time taken will be 3 seconds.

Explanation :

By the 1st equation of motion,

...........(1)

where,

v = final velocity = 8 m/s

u = initial velocity  = 2 m/s

t = time = ?

a = acceleration =

Now put all the given values in the above equation 1, we get:

Hence, the time taken will be 3 seconds.

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 =