- #1
PatF
- 17
- 0
Recently, the New York times ran the obituary of Paul Tibbets who
was the pilot of the plane that dropped an atom bomb on Hiroshima.
At one point the article says:
"At 8:15 a.m. local time, the bomb known to its creators as Little Boy
dropped free at an altitude of 31,000 feet. Forty-three seconds later,
at 1,890 feet above ground zero, it exploded..."
If the above is true, then a little work with a calculator shows it
must have been traveling at about 930 miles per hour if we ignore air
resistance.
This seems quite high to me. It's over 20% faster than the speed of sound
and it seems to me that the shock of going through the sound barrier
might have set off the bomb before it reached it's designated height.
So... Do the above numbers seem reasonable? There is a formula for
terminal speed in Knight's Physics text that indicates the maximum speed
for an object like this to be around 600 miles per hour. Does the air
resistance calculation seem reasonable? (The formula says that terminal
speed is sqrt(4mg/A) where A is the cross sectional area of the object.
Using information on the internet, I found the mass was 4000 kg and I was
able to estimate the area as about 2 square meters. If you want to find
the same information, go into Google and look up "Little Boy", the bomb's
code name.)
Just curious.
--PatF
was the pilot of the plane that dropped an atom bomb on Hiroshima.
At one point the article says:
"At 8:15 a.m. local time, the bomb known to its creators as Little Boy
dropped free at an altitude of 31,000 feet. Forty-three seconds later,
at 1,890 feet above ground zero, it exploded..."
If the above is true, then a little work with a calculator shows it
must have been traveling at about 930 miles per hour if we ignore air
resistance.
This seems quite high to me. It's over 20% faster than the speed of sound
and it seems to me that the shock of going through the sound barrier
might have set off the bomb before it reached it's designated height.
So... Do the above numbers seem reasonable? There is a formula for
terminal speed in Knight's Physics text that indicates the maximum speed
for an object like this to be around 600 miles per hour. Does the air
resistance calculation seem reasonable? (The formula says that terminal
speed is sqrt(4mg/A) where A is the cross sectional area of the object.
Using information on the internet, I found the mass was 4000 kg and I was
able to estimate the area as about 2 square meters. If you want to find
the same information, go into Google and look up "Little Boy", the bomb's
code name.)
Just curious.
--PatF