Question

which of the following best describes the function of crumple zones in reducing the severity of a collision, as discussed in the initial model?
they protect people outside the car by absorbing all impact energy and preventing the car from moving after a crash.
they convert the cars kinetic energy into heat and deformation, thereby increasing the time of impact for occupants.
they prevent a collision from occurring by detecting obstacles and applying the brakes.
they increase the speed of the car so that the driver can quickly get out of the way of an obstacle.

Explanation:

Crumple zones are designed to absorb and dissipate the energy from a collision. By deforming during a crash, they convert the car's kinetic energy into heat and deformation. This process increases the time of impact for occupants. According to the impulse - momentum theorem \(J = F\Delta t=\Delta p\), when the change in momentum \(\Delta p\) (which is related to the car's mass and velocity change) is constant, increasing the time of impact \(\Delta t\) reduces the force \(F\) experienced by the occupants.

Answer:

They convert the car's kinetic energy into heat and deformation, thereby increasing the time of impact for occupants.