Summary
Highlights
Gasoline contains 56 Megajoules of chemical energy per liter, which powers a car by converting it into kinetic energy. However, nearly 80% of this energy is lost as heat. Accelerating a 2-ton car to 60 kph requires about five teaspoons of gas, and maintaining that speed needs more. The kinetic energy of a car moving at 60 kph is comparable to an elephant falling from a three-story building.
When a car stops, its kinetic energy must be dissipated. Brakes convert this energy into heat, while a collision dissipates it through the bending and crumpling of metal. Cars are designed to crumple in a controlled way to prolong the impact duration, reducing the intensity of deceleration and protecting occupants.
Despite design constraints, cars have about 50 cm of crushable space, requiring a resistive force equivalent to a quarter of the space shuttle's main engine thrust during crumpling. Steel rails connect the bumper to the body, absorbing over half the energy, with the rest dissipated by other structural elements. This engineering allows for a high but manageable deceleration rate, similar to what fighter pilots experience.
Before the 1950s, rigid cars caused extreme deceleration in crashes, which was highly dangerous. Modern cars with crumple zones protect occupants by creating a crunchy exterior around a rigid safety cell, making them significantly safer. Ford is highlighted for its role in developing and testing original parts to ensure vehicle safety.