Final answer:
Inertia affects collisions by causing objects to resist changes in their motion. In a car collision, the passengers continue to move forward even when the car stops abruptly due to their inertia. Seat belts are important as they provide a restraining force to stop the passengers. The car absorbs some of the energy of the collision by deforming and crumpling, which helps to reduce the force acting on the passengers.
Step-by-step explanation:
Inertia affects collisions in multiple ways. Newton's first law of motion states that an object at rest will remain at rest and an object in motion will remain in motion with constant velocity, unless acted upon by an external force. This means that objects tend to resist changes in their motion. In collisions, inertia explains the crumpling of a car. When a car collides, the passengers inside the car will continue to move forward due to their inertia, even when the car stops abruptly. This is why seat belts are important as they provide a restraining force to stop the passengers. However, the car absorbs some of the energy of the collision by deforming and crumpling, which helps to reduce the force acting on the passengers.