A balloon drifts 30 m toward the east in 8 s; then the wind suddenly changes and the balloon flies 50 m toward the west in the next 7 s. a. What distance did it travel during the first 10 s?
b. What distance did it travel during the next 5 s?
c. What total distance did it travel?

j. What was its average velocity during the first 10 s?
k. What was its average velocity during the next 5 s?
l. What was its average velocity for the entire trip?

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 =

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.