Find the magnitude and direction of the vectors with components:
a Ax=-4.0 cm, Ay=-4.0 cm
b Ax=124 km, Ay=-158 km
c Ax=0, Ay=-5.0m
d Ax=8.0N, Ay= 0

Given a position vector →v=⟨a,b⟩,the magnitude is found by |v|=√a2+b2. The direction is equal to the angle formed with the x-axis, or with the y-axis, depending on the application. For a position vector, the direction is found by tanθ=(ba)⇒θ=tan−1(ba), as illustrated in Figure 8.8

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 =