AP Physics Assignment                                                                               Brockport High School NY USA
Chapter 1 Fermi Problems of Estimation                                                  Mr Keefer

The method of obtaining a quick approximation to a seemingly difficult mathematical process by using a series of "educated guesses" and rounded calculations is attributed to the nuclear physicist Enrico Fermi.  Your logical imagination is important in solving the following problems.
1. Given normal lifetime expectations, how many more seconds do you have yet to live?
2.  A tuning fork is vibrated at the highest frequency audible to humans.  The tuning fork can still be heard 20 seconds after it is struck.  How many vibrations have occurred during the 20 seconds?
3. 
What is the mass in kilograms of the student body at Brockport High School?
4.  If five students submerge themselves at the same time in a cylinder of water 3 meters deep and 2 meters in diameter, how many centimeters would the water rise?
5.  Suppose five of you could stand on each others' shoulders to form a human tower.  Now imagine someone making a pile of $100 bills as tall as the human tower.  How much money would it take?
6.  Annually, Planet Earth accretes approximately 3 x 107 kg of interplanetary dust particles from the zodiacal cloud.  How many kilograms of interplanetary dust landed on the roof of Brockport High School?
7.  What percent of the sun
=s radiation strikes the earth?
8.  How many seconds does it take red light to pass through a methane molecule?
9. 
Estimate the total number of hairs on your head.
10.  The solar wind passing by the earth blows away 3 kg of material each second.  Assuming the Sun will last forever and the earth accrues no new material, how many years will pass before the earth disappears?
11. 
How fast does human hair grow?

Facts for Fun
world population (1983)                                         4.7 x 109 people
world population (2005)                                         6.5 x 109 people
world population (1650)                                         5 x 108 people
domestic water use in U.S.                                    1.3 x 103 m3/s
age of Universe                                                       3.3 x 1017 s
age of Earth                                                             1.6 x 1017 s
diameter of human hair                                           1 x 10-4 m
galaxies in the universe                                         5 x 1010
atomic mass unit (amu)                                          1.660565 x 10-27 kg
kinetic energy of earth                                           2.6 x 1033 J
thrust of a Boeing 747 jet engine                        7.7 x 105 N
pH of acid rain                                                          4 x 100
sound causing ruptured eardrums                       1.6 x 102 dB
voltage between a Boeing 747's wingtips             7.5 x 10-1 V
boiling point of helium                                        4.2 x 100 K
mass of an electron at rest                                   9.109534 x 10-31 kg
upper hearing limit of a teenager                         2 x 104 Hz
mass of delivered junk mail in U.S.                      4.4 x 101 kg/s
power of hurricane                                                   2 x 1013 W
wavelength of tsunami                                          2 x 105 m
year                                                                        3.1556926 x 107 s
velocity of nerve signal                                         4.9 x 101 m/s
surface area of average man                              1.8 x 100 m2   
orbital radius of Pluto                                           5.909 x 1012 m
orbital radius of Earth                                           1.49457 x 1011m
mass of red blood cell                                          9 x10-14 kg
T of caffeine in adult human                          1.3 x104 s
air intake of average woman                            2.44 10-4m3/s


Back to the Brockport High School Science Department