March 12th, 2013

Tuesday Trivia Challenge from Bryan Litz, Ballistics Guru

Here’s a Ballistics Trivia challenge, put together by Bryan Litz of Applied Ballistics LLC. Bryan is Berger Bullets’ Ballistician and the author of Applied Ballistics for Long Range Shooting. Bryan posed the following Ballistics Question about Kinetic Energy and Aerodynamic Drag:

Bryan Litz Ballistics TriviaConsider a .30 caliber 175 grain bullet with a G7 BC of .259 (Berger 175 OTM) fired level at a muzzle velocity of 2650 fps in standard (ICAO) sea level conditions.

As this bullet flies downrange, it loses velocity due to aerodynamic drag. As the velocity of the bullet decays, so does its Kinetic Energy (in ft-lbs). The Kinetic Energy lost by the bullet in a given amount of time can be defined in terms of power.

Another way to think about this is that the aerodynamic drag on the bullet can be expressed in terms of power, calculated from the projectile’s change in Kinetic Energy over flight time.

Question: How much power (expressed in Watts) is applied to the bullet by aerodynamic drag on average over:

A) 500 yards?
B) 1000 yards?
C) 1500 yards?

Guesses are welcome, but this one can be calculated exactly.

Bryan Litz Ballistics Trivia

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