Ahorizontal force of 50 n is required to push a wagon across a sidewalk at a constant speed.
a. what is the net (unbalanced) force acting on the wagon?
b. what forces are acting on the wagon?
c. if the mass on the box increased, use newton's law to explain what must change to get the object moving at a constant speed.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2

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 =