Name: Riad S.
My coworkers and I are disputing the trajectory of a bullet.
If I was to shoot a bullet with the gun barrel horizontal, when the bullet
comes to rest, will it land directly in line with the barrel or would it
be slightly to the left or slightly to the right of the barrel? To make
sure there is no confusion, we are assuming there is no wind at all.
From my knowledge, the bullet rotates clockwise out of the barrel and my
assumption is that it will land to the left.
Hi, Riad !!
I cannot see a reason why the bullet should land
to the left or right. The friction forces will act in all
directions alongside the circumference of the bullet.
The aerodinamyc design allows penetration in the
air and friction forces will tend to slow down the speed.
Due to differences in pressure between the upper
and lower areas, there will be a small force acting
upwards, but vertical, and have no influence on the
trajectory. Then comes into action the gravity acceleration
with vertical direction. So, if there is no wind, there
will not occur a change of trajectory outside the
Why is that you believe that the bullet will land to the left ??
It is my opinion that the spiraling action caused by the riflings in the
barrel will cause EQUAL amounts of friction from all points of contact with
the barrel as it traverses the length of the barrel. So as the slug rotates
down the length of the barrel there will be no preferential slowing to
The speed of the bullet (assuming perfect symmetry, smoothness, etc.) is so
fast and the viscosity of air so small that the bullet's spin would have
little effect on its trajectory. That is there is very little drag due to
the air. What may be surprising is that the bullet you fired will hit the
ground at the same instant as a bullet you dropped from your hand at the
moment of firing -- again with all the simplifying assumptions.
Click here to return to the Physics Archives
Update: June 2012