Boyle's Law states that when a sample of gas is compressed at a constant temperature, the pressure P P and volume V V satisfy the equation P V = C PV=C, where C C is a constant. Suppose that at a certain instant the volume is 1000 cm 3 1000 cm3, the pressure is 80 kPa 80 kPa, and the pressure is increasing at a rate of 40 kPa/min 40 kPa/min. At what rate is the volume decreasing at this instant?

the volume decreases at the rate of 500cm³ in 1 min

Explanation:

given

v = 1000cm³, p = 80kPa, Δp/t= 40kPa/min

PV=C

vΔp + pΔv = 0

differentiate with respect to time

v(Δp/t) + p(Δv/t) = 0

(1000cm³)(40kPa/min) + 80kPa(Δv/t) = 0

40000 + 80kPa(Δv/t) = 0

Δv/t = -40000/80

= -500cm³/min

the volume decreases at the rate of 500cm³ in 1 min

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 =