what is the function of seat belts and air bags in automobiles? need a physics answer!?

Answer 1

Simply put, to save your life by increasing the time in which you come to a complete stop.

We can first look at the seatbelt scenario. Seat belts come in two varieties, the stretching and non-stretching kinds. Since you want a Physics answer here goes.

Let's look at a car that's moving at about 30 miles/hr or about 13.4 m/s. Let's also assume that we have a man in the car whose mass is about 70 kg.

If there is no seatbelt, the distance the driver moves in a crash is determined by the distance from the steering column to the windscreen. This means the driver crashes, moves forward to the steering column and then starts decelerating. He hits the windscreen. This distance is typically about a few inches, lets say about 0.2 ft.

So

v^2 = u^2 +2(a)(s)

We get a deceleration of about

a= -1500ms^-2

This is about 150g's

Now what a seatbelt does is stop you with the car. This will typically give you a stopping distance that is about 4 to 5 times more than if you weren't wearing the seatbelt at all!

Let's say that the stopping distance is about 0.3m

Using the above equation, we find that we get a deceleration of about 300ms^-2. This is about 30g's

Now for the stretching seatbelt case. the stretching seatbelt extends the distance under which the driver stops. You cna see from the above this is a good thing. The seatbelt can typically increase the stopping distance by about 50%. So the stopping distance from above increases to 0.45m

Again plugging these values into the above equation we get a deceleration of about 200ms^-2. This comes to about 20g's

So the function of the seatbelt is to increase the stopping distance of the driver or passenger. Thisreduces the deceleration of the person and hence the forces they experience.

So what's the deal with the airbag??

Well, the airbag doesn't decrease the forces on the passenger or driver. The forces will be the same. In a crash the seatbelt is strapped across the person's ribcage. This is where most of the forces are centered. The airbag is basically a fluid filled bag and so it allows the force to be distributed over a greater area. This reduces the pressure on the body.

Now this does not mean that you should not use a seatbelt. The seatbelt also prevents you from flying about as the car crashes. The airbag will help in cushioning the impact.

Hope this helps.

Answer 2

the function of seat belts and air bags are to protect u from the hitting on the steering by giving u a speed resistance

Answer 3

it could make no difference. If it even made a difference, you may by no ability observe. All of those issues are electronically controlled, different than for the seat belt, this is spring-loaded. the burden component for those products is negligible (all of those advantageous aspects blended upload consistent with possibility 20 or 30 pounds on your motor vehicle). you may get in worry in case you have been to stress the motor vehicle with out seat belts. removing the airbags could reason issues once you visit sell the motor vehicle because you would be required to demonstrate to any ability customer that the motor vehicle does not have them. In some states, you need to get in worry for it. relatively, the risk and the implications of removing all that "extraneous" risk-free practices kit are far greater desirable than any won gas financial equipment or convenience.

Answer 4

To distribute the force of deceleration over a larger and/or stronger area of the body (pelvis) and over a longer period of time vs. the windshield so as to minimize peak pressure and injury.

Answer 5

They both constraint and damp motion.

Seatbelts constraint your body from flying out of the car as the hits something.

Both seatbelts and airbags act as dampers trying to reduce the speed of ur body hitting the car parts.

Answer 6

Seat belts and air bags are:

RANGE OF MOTION restraints.
.

Answer 7

seat belt stabilize you against forward momentum, air bag slows down the momentum of your body and absorbs impact. you can break it down from there

Answer 8

To cause a body in motion to cease it's motion without causing undo harm to the body that was originally in motion.

Newton's law...vs...slamming the breaks.

Answer 9

because force = change in momentum over change in time if you can increase the time of the impact you will decrease net force.