Final answer:
The force experienced by a driver in a head-on collision is calculated using the formula F = ma. Safety devices like seat belts and airbags reduce the force by extending the time over which the driver is brought to a stop. Without these devices, the force would be significantly higher, leading to more severe injuries.
Step-by-step explanation:
The question involves a head-on motor vehicle collision with a scenario where a seat belt reduces the injuries sustained by a driver. The physics behind the impact and the beneficial effects of safety devices like seat belts and airbags relate to the principles of motion and force. To determine the force experienced by the driver during the collision, we use the formula F = ma, where F is the force, m is the mass of the person, and a is the acceleration (or deceleration in this case). For a car crashing into a tree and stopping in 0.26 seconds with a passenger of 70 kg, the force exerted by the seat belt can be calculated using the change in velocity (10 m/s to 0 m/s) and the time span of the deceleration (0.26 s). Assuming that the passenger was brought to a halt by the seat belt, the deceleration a can be found using the equation a = Δv / t, where Δv is the change in velocity and t is the time taken to stop.
Without the seat belt and the airbag, the force experienced by the driver would be significantly higher because the collision time would be shorter (0.20 s versus 0.26 s), resulting in a greater acceleration and hence a greater force based on the same formula F = ma. It is evident that seat belts and airbags play a critical role in reducing the magnitude of forces acting on individuals during car collisions thus minimizing injuries such as seat belt contusions and back pain.