Answer
The design of automobile bumpers has changed over the years to improve safety and reduce damage in the event of a collision. Traditional steel bumpers were designed to resist impact and protect the vehicle's body from damage. However, they were often rigid and did not absorb much of the energy of a collision, which meant that the impact was transferred directly to the occupants of the vehicle, resulting in more severe injuries.
Modern bumpers are designed to absorb the impact of a collision and reduce the force that is transferred to the vehicle's occupants. They are made from materials such as plastic, aluminum, or composites that are designed to crumple or collapse upon impact. This crumpling absorbs the energy of the collision, which helps to reduce the force that is transferred to the vehicle's occupants.
This approach to bumper design is called "crumple zones," which are areas of the vehicle that are designed to deform in a collision. By using crumple zones, the impact energy is absorbed and dissipated throughout the vehicle's structure, which reduces the likelihood of injury to the occupants. The use of crumple zones also helps to reduce the damage to the vehicle, as the energy of the collision is absorbed by the structure of the vehicle, rather than by the bodywork.
Overall, the shift towards bumpers that crumple or collapse upon impact has been driven by a desire to improve safety for vehicle occupants and reduce the damage caused by collisions. While these modern bumpers may not provide the same level of protection for the vehicle's body as traditional steel bumpers, they offer a significant improvement in terms of occupant safety.
Work Step by Step
This is related to the equation for impulse and force
$J= \Delta p= F \Delta t$
