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Re: [Phys-l] Final velocity of bullets



While real bullets tumble and are a more complex shape, I just ran a spreadsheet simulation using a 10 gram, 0.6cm spherical bullet. At initial velocities of 1000 m/s (but with the same results at 500 m/s) I'm getting the same final velocity of the bullet fired anywhere from 5 degrees to 90 degrees (within a very small range). Namely, about 50 m/s. I used a time increment of .01 seconds, a damping factor b = .5xCxrhoxA with C = .5 and an overall b of .0000387. I let g stay constant at 9.81 and assumed a v-squared dependency. The flight times ranges from 12 to 27 seconds for the 1000 m/s initial velocity. If you want to try this, the only complication is that the air-resistance induced acceleration changes sign after the bullet starts down. I just adjusted that manually with each trial (changing angle).

I think this might suggest that once the bullet starts tumbling (if it does) then the final velocity really doesn't depend on the angle fired. Can anybody confirm or refute these calculations?

Rick

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Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
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Free Physics Software
PC & Mac
www.saintmarys.edu/~rtarara/software.html
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