Question

Why should we wear safety seat belts in a car

Answer 1

due to inertia.
if a moving car stops suddenly then due to inertia of motion we could fall in front and we could get harmed.

Answer 2

Seat belts provide safety to passengers (which is based on the second law of motion). In case of sudden brakes the momentum of the car reduces to zero in a very short time. if brakes are applied suddenly to a fast moving car, then the person without using seat belts may get injured due to inertia(the car will stop and the portion of the person's body which are in contact with the car will stop too. But the portions which are not in contact will still have the momentum, for which they move front-wards, resulting the person to get injured). Do, to prevent the person from self accident, seat belts are advised to be worn.

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