1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
STALIN [3.7K]
3 years ago
7

Enrico Fermi (1901–1954) was a famous physicist who liked to pose what are now known as Fermi problems, in which several assumpt

ions are made in order to make a seemingly impossible estimate. Probably the most famous example is the estimate of the number of piano tuners in Chicago using the approximate population of the city and assumptions about how many households have pianos, how often pianos need tuning, and how many hours a given tuner works in a year. Another famous example of a Fermi problem is "Caesar's last breath," which estimates that you, right now, are breathing some of the molecules exhaled by Julius Caesar just before he died. The assumptions made are: The gas molecules from Caesar's last breath are now evenly dispersed in the atmosphere. The atmosphere is 50 km thick, has an average temperature of 15 °C , and an average pressure of 0.20 atm . The radius of the Earth is about 6400 km . The volume of a single human breath is roughly 500 mL . Perform the calculations, reporting all answers to two significant figures.
Physics
1 answer:
Katarina [22]3 years ago
5 0

Answer:

Explanation:

(a)

Since the earth is assumed to be a sphere.

Volume of atmosphere = volume of (earth +atm osphere) — volume of earth

= \frac{4}{3}\pi(6400+ 50)^3 -  \frac{4}{3}\pi (6400)
^3\\\\=  \frac{4}{3}\pi(6192125000) km’^3\\= 2.6\times 10^{19} m^3

Hence the volume of atmosphere is 2.6\times 10^{19} m^3

(b)

Write the ideal gas equation as foll ows:

PV = nRT\\\\n\frac{0.20atm\times 2.6\times10^{19} m^3}{0.08206L\, atm/mok\, K \times (15+273+15)K}\times \frac{1L}{10^{-3}m^3}\\\\= 2.20\times 10^{20} moles

no.\, of\, molecules = 2.20\times 10^{20} moles \times \frac{6.022\times10^{23}\,molecules}{1mole}= 13.3\times10^{43} molecules


Hence the required molecules is 13.3\times10^{43} molecules


(c)

Write the ideal gas equation as follows:

PV =nRT
\\\\n=\frac{1.0 atm \times 0.5L
}{0.08206 L\, atm/mol\,K \times (37 +273.1 5)K} = 0.0196 moles

no.\, of\, molecules = 0.0196 moles \times\frac{6.022\times10^{23} molecules}
{Imole}= 1.2\times 10^{23} molecules

Hence the required molecules in Caesar breath is 1.2\times 10^{23} molecules

(d)

Volume fraction in Caesar last breath is as follows:  

Fraction,\, X =\frac{12\times 10 molecules}{13.3\times 10^{43} \,molecules}= 9.0\times 10\, molecule/air\, molecule}

(e)

Since the volume capacity of the human body is 500 mL.

Volume\, of\, Caesar\, nreath\, inhale\, is =\frac{ 12\times 10^{22}\, molecules}{breath}\times \frac{9.0\times10^{-23} molecule}{air\, molecule}\\\\= 1.08 molecule/breath

You might be interested in
Two bicyclists are accelerating forward in a straight line, and Biker 1 has less mass than Biker 2. If the net force on the bike
Solnce55 [7]

If  Biker 1 has less mass than Biker 2 it the follows that biker 1 has a greater acceleration than Biker 2.​

<h3>What is the Newton second law?</h3>

The Newton second law gives the relationship between the force and the acceleration. We know that; acceleration = Force/mass.

Now if Biker 1 has less mass than Biker 2 it the follows that biker 1 has a greater acceleration than Biker 2.​

Learn more about Newton's law:brainly.com/question/27573481

#SPJ1

4 0
1 year ago
Think about a typical school day. In the space provided below, describe how each of the different forms of energy we have learne
Nezavi [6.7K]

Answer:

During a typical school day all forms of eneergy is being utilised and also transfer of energy takes place from one form to another.

Explanation:

Chemical energy- A bunsen burner burning a beaker filled with water.

Heat energy- The water in the beaker absorbing the heat from the burner.

Electrical energy- Running Fans and lights in a classroom by switches.

Solar energy- Solar energy harnessed by solar panels to run the fans and lights by converting it into electrical energy.

Potential energy- A ball being held by a student at a certain height possesses energy due to gravity.

Kinetic energy- The same ball being left by the boy from a certain height produces kinetic energy

3 0
2 years ago
Read 2 more answers
Mass (kg)
Tju [1.3M]

Mass.

Because mass doesn't depend on weight but weight depends on mass.

8 0
3 years ago
Read 2 more answers
In a lever, the effort arm is two times as long as the load arm. The resultant force will be
jasenka [17]
Answer is B. 

In a lever, the effort arm is 2 times as a long as the load arm. The resultant force will be twice the applied force.

Hope it helped you.

-
Charlie
5 0
3 years ago
Read 2 more answers
Se aplica una fuerza neta de 25 N a una masa de 10 kg. ¿Cuál es la aceleración dada a la masa?
lys-0071 [83]

Answer:

Se queda

Explanation:

Porque 10 kg es más que 25N

4 0
3 years ago
Other questions:
  • How much of the matter in the universe is comprised of atoms?
    11·2 answers
  • Explain why the speed of a sled is increases as it moves down a snow -covered hill, even though no one is pushing the sled
    10·1 answer
  • What does a thermostat do if it gets too cool? ____________________________________ 2. what does a thermostat do if it gets too
    13·1 answer
  • Julia can swim at 3.5 km/h in still water. She attempts to head straight north
    5·1 answer
  • What is the predicted result when two different materials of equal mass absorb the same amount of energy by heat flow?
    6·1 answer
  • Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined plane and allowed t
    7·1 answer
  • Why are units of measurement useful?
    13·1 answer
  • Donner le lien entre la consommation d,eau et l,aspect de votre peau c,est un dm note reponse​
    5·1 answer
  • How does the circuit change when the wire is added? a closed circuit occurs and makes all bulbs turn off. an open circuit occurs
    15·1 answer
  • a car with a mass of 1000-liogram accerlerates from rest, and travels a distanceof 48 meters druing its first 4.0 seconds of uni
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!