"seat belts save lives" is not just a safety catch phrase but the law to wear seat belts in a moving car. why would newton say that we wear seat belts? a) an object in motion tends to stay in motion unless acting upon by an external force. b) the idiom that every action has an equal and opposite reaction applies to this case. c) the acceleration and mass of the object are directly proportional to the force applied. d) driver mass and inertia accelerate with the stopping force due to the unbalanced forces.

A. An object in motion tends to stay in motion unless acting upon by an external force.

Step-by-step explanation:

We have the statement, 'Seat belt save lives'.

Now, wearing seat belts are important because when an object is in motion, it stays in motion unless an external force is applied.

So, during some collision, seat belts act as the external force to provide a break to the body, which will help in preventing injuries.

Hence, we get that,

Newton says that we wear seat belts because, 'an object in motion tends to stay in motion unless acting upon by an external force'.