Physics question

Rich S. wrote:
"abripl" wrote in message
oups.com...
With bullet/plane(s) relative horizontal speed of 820ft/s, the other
plane reaches the bullet position in (50x3)/820 =3D 0.183 sec (pretty
slow bullet). In that time the bullet falls a vertical distance of 0.5
x 32 x 0.183 x 0.183 ft =3D 0.536 ft. If the messer plane bottom was at
least 0.537 ft (about 7 inches) below bullet firing vertical position
its gona hit the other plane.

Half a foot at 50 yards? I misrememeberd that a 45 drops half an
inch at 50 yards. How embarassing.


Nope. You are assuming "the other plane reaches the bullet position . . .=
"=2E
It never reaches the bullet's position because it is traveling at 90=B0 t=
o the
flight path of the B-17. If it was following the B-17, it could possibly =
run
into the bullet, but only at its foward velocity. The bullet has only a
downward component relative to the Earth. (Ignoring minor variations, i. =
e=2E
coriolis force & wind velocity.)


You're still assuming he's leading the ME-109 as if the gunner
were in a fixed location. He's assuming the gunner is actually
trying to hit the plane, and smart enough to figure out how
so that he times his shot *correctly*. You're both assuming
he fires straight back. He can hit the Me-109 by firing straight
back, but ONLY if he fires exactly as B-17 crosses the flight
path of the Me-109, and only if the Me-109 is fast enough or
close enough to get there before the bullet drops out of the
flight path of the Me-109. If the Me-109 is at a range of 50
yards, and no slower than the bullet the bullet will be no
more than 7 inches lower than the muzzle of the gun and will
still hit the Me-109 assuming the two planes are at the same
altitude.

Here is an example:

Both planes are at the same altitude.
The gunner fires straight back and level when the B-17
crosses the flight path ahead of the ME-109. At that
moment, the Me-109 is at a range of 50 yards, e.g. it
is 50 yards directly to the right of the gunner and
flying from right to left, and also flying at 820 ft/s.
If you think that bullet misses, calculate by how much.
Now do that again, assuming the Me-109 is a bit faster,
say, 900 ft/s.

There is a range of realistic speeds and altitudes
for the Me 109 for which it will be hit, and a larger range
of speeds an altitudes for which it can be hit if the gunner
is allowed to aim up or down, larger still if he can aim from
left to right even though in all cases the ME-109 is flying
at 90 degrees to the flight path of the B-17.

--=20

FF