Pyramid Science

This is for researching science-based articles and the contents are for personal use although a wider potential interest is possible and so they are left here to view. No medical advice is given and a qualified medical practitioner should be consulted if any concerns are raised. Comments have been disabled, but any and all unsolicited or unauthorised links are absolutely disavowed.

Tuesday, March 04, 2008

Speed, Power And Destructive Force

The inter-relationship of the detail is complex between speed, power and destructive force, but the fundamental concept is not. Driving fast is very different from being a 'fast driver'. Essentially, anyone capable of driving is capable of driving fast. This does not imply driving safely. An experienced driver with awareness and quick reaction times has only the potential of being a fast and safe driver. Speed translates to a highly destructive force.

Constant speed returns the best economy, but achieving the ideal speed is the most fuel expensive in terms of the energy requirement. Acceleration is the rate of change in velocity and is the costliest in terms of fuel (energy) usage. An example would be to bring a tonne weight from zero kmph (standing still) to 50 kmph. Energy has to be consumed to create the momentum or potential energy. A rock standing at rest on a ledge at the top of a mountain has potential energy that will be converted into kinetic energy if pushed over the edge. Somehow energy was consumed to bring that rock up to the altitude of the ledge. The energy of a collapsing building is the sum of all that energy required to build it in the first place, which may have taken many months and used up thousands of man-hours in effort and energy expenditure. To fall to the ground takes only a few seconds.

The relationship between wind resistance and power to speed is non-linear. The kinetic energy is a square function: twice the speed results in 4 times the power. Three times the speed results in a 9-fold the energy output, 16-fold from four times the speed and so on. Energy out requires energy in, so the cost overhead is huge for the apparent gain in performance. An upward curve that becomes more expensive the higher it gets. The gradient of the curve becomes less and the increase in speed for the power input progressively gets smaller. It is why a high velocity bullet is so destructive. A larger and slower moving missile could have similar potential, but a faster moving and much heavier missile will accordingly have many times the destructive power. A missile fired from a fast moving warplane will already have the potential energy from travelling as part of the aircraft, but additional speed is acquired from it's launch. The acceleration from 'zero' (aircraft velocity) to final velocity will translate to an enormous kinetic energy. This total energy forms an integral part of the moving object. Impact constitutes an effectively instantaneous velocity change to zero kmph (deceleration) and releases this total energy. The associated destructive force excludes any explosive force.

In a car crash, the passengers are the effective missiles that have potential energy by moving at the velocity of the vehicle. If a the vehicle suddenly slows and stops due to impact the passengers become the moving objects with the kinetic energy of continued motion until further impact stops that. The internal organs will travel at speed and be ruptured and torn when the body stops, but the organs don't. The energy is then imparted to the collision object. If this object doesn't move (like a solid brick wall) then all that energy is turned inwardly to destroy the passenger. A moving target may deflect the energy to create a survivable collision, but (almost) certainly the crash will be fatal. The same situation occurs in brain impact injury. The brain will suffer an enormous trauma at the initial impact site and suffer a second impact at the opposite side of the skull as it contacts the hard surface. The brain always suffers a double impact injury and the associated tearing and rupture of blood vessels within the head. Head injuries can be terrible if they are survived in an accident. Similar issues are present in any contact sport. There are very few survivors from an air crash. There is a size dependency and humans are relatively tiny.

The Earth as a massive object doesn't move much if hit by a very small falling object (plane), however fast that object travels and the crushing impact could be from around 600mph to zero mph in milliseconds. The human body would be literally torn apart internally. Completely non-survivable