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When an element of mass is offset from the axis of rotation, centrifugal force will tend to pull the mass outward. The elastic properties of the shaft will act to restore the “straightness”. If the frequency of rotation is equal to one of the resonant frequencies of the shaft, whirling will occur.
This speed is the asymptotic limiting value of the speed, and the forces acting on the body balance each other more and more closely as the terminal speed is approached. In this example, a speed of 50.0% of terminal speed is reached after only about 3 seconds, while it takes 8 seconds to reach 90%, 15 seconds to reach 99%, and so on.
N - The mass of a tamper shell or sheet on the other side of the explosive charge, if present - The energy per mass of an explosive that ends up as kinetic energy - The Gurney constant for a given explosive. This is expressed in units of velocity (millimeters per microsecond, for example) and compares the relative flyer velocity produced by ...
Per the Barometric Formula page the density change is 1%/80m. And, looking at the terminal velocity formula, I think terminal velocity should change as about half of the density change, so 1%/160m seems correct. So I just edited the 50 to 80...someone who knows, double-check me? Thanks, --Shyland 19:48, 31 October 2006 (UTC)
Terminal ballistics is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target. Bullet design (as well as the velocity of impact) largely determines the effectiveness of penetration.
ρ p is the mass density of the sphere [kg/m 3] ρ f is the mass density of the fluid [kg/m 3] g is the gravitational acceleration [m/s 2] Requiring the force balance F d = F e and solving for the velocity v gives the terminal velocity v s.
The terminal velocity depends on many factors including mass, drag coefficient, and relative surface area and will only be achieved if the fall is from sufficient altitude. A typical skydiver in a spread-eagle position will reach terminal velocity after about 12 seconds, during which time they will have fallen around 450 m (1,500 ft).
If the impactor has pushed a mass equal to its own mass at this speed, its whole momentum has been transferred to the mass in front of it and the impactor will be stopped. For a cylindrical impactor, by the time it stops, it will have penetrated to a depth that is equal to its own length times its relative density with respect to the target ...