Bullet Trajectory ```Name: James Status: educator Age: 40s Location: N/A Country: N/A Date: 2000-2001 ``` Question: Does a bullet fired from a rifle ever get higher than the barrel assuming that the barrel is level when fired? I have students that argue that the bullet rises. I believe that this misconception occurs because they misunderstand trajectory charts. I have told students that a bullet is always falling after firing. The reason the bullet is shown higher at the mid range point is because the barrel is elevated as a result of the scopes setting. Am I confused about bullet trajectory from a perfectly horizonal barrel? Replies: No, you are right, they are confused. Richard Barrans No you are correct about a perfectly level and true barrel, the bullet is always falling. There is a rise due to the design of the rifle and scope design as you mentioned, but regardless gravity is always working. There is another experiment to try, or to show your students and may be difficult to explain without actually drawing it but if you were to take a low velocity ejector such as a steal ball propelled by a spring through a short barrel pointing up at a 45 degree angle from the horizon and the barrel was aimed at a suspended tin can maybe 5 ft higher, and the can was dropped at the moment the ball was fired it would still hit the can since both objects are now falling at the same rate. Take a look in a physics book I know this is a well known example, although it is tricky to perform just because of the timing issue. Michael Baldwin No. You're right. The vertical motion of a bullet can be thought of as completely independent of its horizontal motion. The vertical motion is always the same, whether you fire the bullet out of a rifle or drop it by hand. It just falls, like everything else. Tim Mooney No James, you are not confused. The only way the bullet would rise is if there is a force to move it. Assuming that there is only gravity - pulling down- and the force of the gun - pushing horizontally - there would be no force moving the bullet up. Often the bullet is pictured arcing up and down portraying (I assume) striking a target at the same level as the muzzle of the gun... Larry Krengel I believe Newton agrees with you, unless the bullet can "hydroplane" in the atmosphere. Your explanation of a parallax correction seems reasonable as a plausible explanation why it may be shown "rising" a bit. Vince Calder Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs