Pregunta de Natural Sciences and their Technologies #019e354a
Muitas pessoas ainda se espantam com o fato de um passageiro sair ileso de um acidente de carro em que a frente do veículo fica completamente amassada. Na verdade, a destruição intencional da frente dos automóveis modernos é um recurso de segurança conhecido como zona de deformação (crumple zone). O objetivo desse projeto é aumentar o tempo de desaceleração do veículo durante uma colisão, o que diminui a força média exercida sobre os passageiros, reduzindo a gravidade dos ferimentos.
Considering the car, its occupants, and the wall in the figure as an isolated system, the crumple zone increases passenger safety because, during a collision, the deformation of the car's structure...
It activates the vehicle's airbags.
It absorbs the kinetic energy of the system.
It consumes the momentum of the system.
It creates a protective barrier for its occupants.
decreases the speed of the center of mass of the system
Explicación Oficial / Explicaciones de la Comunidad
Analysis of the "Crumple Zone" Function
The correct answer is option A. B) absorbs the kinetic energy of the system.
1. The Physical Principle of Collision
A collision is an event where there is a rapid transfer of energy and momentum. A moving car possesses a large amount of... kinetic energy (energy of motion). For passengers to survive a sudden stop, such as a crash, this energy needs to be dissipated safely, that is, without being transferred to the occupants.
2. The Function of the "Crumple Zone" (Deformable Region)
The "deformable region" is designed precisely to fulfill this function. The process of crushing and deforming the car's metal structure requires physical work. This work transforms the... kinetic energy converting the vehicle's energy into other forms, such as heat and sound.
- As it deforms, the front of the car absorbs the energy of the impactThis means that a significant portion of the kinetic energy the car possessed before the collision is "spent" crushing the bodywork, instead of being transferred to the passenger compartment. * Consequently, the force of the impact reaching the occupants is drastically reduced, increasing their chances of survival. The passenger cabin, on the other hand, is designed to be as rigid as possible, so as not to deform and to protect the occupants' living space.
3. Evaluation of Other Alternatives
- A) Activates the vehicle's airbags: Incorrect. Airbags are deployed by deceleration sensors, not directly by structural deformation. They are systems that work together, but one is not the cause of the other. * C) consumes the momentum of the system: Incorrect. According to the principle of conservation of momentum, the total momentum of an isolated system is not "consumed," but rather conserved or transferred. * D) It creates a protective barrier for its occupants: Incorrect, because it is inaccurate. The specific function of deformation It's not just about being a barrier, but about managing the energy of the impact. As the text points out, a more rigid barrier would be less safe. * E) decreases the velocity of the system's center of mass: Incorrect. The car's speed will go to zero anyway. The function of the crumple zone is to increase the... time which leads to this stop happening. By increasing the impact time, the force felt by the passengers decreases (according to the impulse theorem), but the main physical function of the deformation itself is the dissipation of energy.
4. Conclusion
The crumple zone increases passenger safety because, during a collision, the deformation of the car's structure... absorbs the kinetic energy of the system, converting it into other forms of energy and preventing it from being transferred to the occupants.