An airbag significantly reduces the impact force experienced during a collision by extending the duration of the crash.

In the event of a car crash, both the vehicle and its occupants undergo rapid deceleration. This abrupt change in velocity produces a substantial force, which can be expressed mathematically as $F = ma$, where $F$ represents force, $m$ is mass, and $a$ is acceleration. The primary function of an airbag is to lessen the impact of this force on the human body.

When a collision occurs, sensors within the vehicle detect the sudden deceleration and activate the airbag deployment mechanism. The airbag inflates quickly, creating a soft cushion that occupants collide with instead of the rigid surfaces of the car’s interior. This inflation process effectively increases the time duration of the collision. According to the impulse-momentum theorem, the force experienced by an object can be defined as the change in momentum divided by the time interval over which this change occurs:

$F = \frac{\Delta p}{\Delta t}$

By extending the time of collision, the airbag reduces the force experienced by the occupant.

In addition to increasing collision time, the airbag also expands the area over which the force is distributed. When an occupant strikes the airbag, the force is distributed over a larger surface area compared to a collision with a solid surface. This distribution lowers the pressure on any single point of the occupant’s body, further decreasing the likelihood of injury.

The airbag system exemplifies the practical application of fundamental physics principles, particularly Newton’s laws of motion and the impulse-momentum theorem. This technology highlights how a thorough understanding of these principles can lead to innovations that save lives. It is also essential to recognize that while airbags greatly diminish the risk of severe injury during a crash, their effectiveness is maximized when used in conjunction with seat belts, which help secure occupants and prevent ejection from the vehicle.

IB Physics Tutor Summary: In summary, an airbag reduces the force experienced during a crash by increasing both the duration of the collision and the area over which the force acts. It deploys rapidly to provide a cushioning effect, thereby lowering the pressure on any single point of the body. This technology, grounded in the principles of physics such as Newton’s laws, substantially decreases the risk of injury when used alongside seat belts.