Which law of motion accounts for seatbelts

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In summary, the conversation discusses the best choice between Newton's Law 1, 2, or 3 and whether wearing a seatbelt and stopping would be considered Newton's 1st law. The speaker believes that Newton's 3rd law is the best choice and that the seatbelt exerts a force to stop the person from going forward. However, another person questions the reasoning and asks if there is any consideration of Newton's 2nd law. The conversation ends with the question of why one would wear a seatbelt and if stopping would be considered Newton's 1st law.
  • #1
jakeginobi
1. The problem statement, all variables and
given/known data
What would the best choice be:Newton's Law 1 or 2 or 3. Wearing a seatbelt and when it stops.

Homework Equations


N/A

The Attempt at a Solution


I thought the best choice would be 3 because for every action there's a reaction. I don't know any responses that fit to Newton's Law 1. I don't think it's Law 1 because objects tend to stay in motion/rest unless acted by external force, and there was an unbalanced force that caused change - or does it also imply that if an unbalance force is exerted it fits Newton's Law 1? The seat belt causes an external force and Law 1 states that the net force would be 0

One more question why would this be Newton's 1st law?
"a frog leaping upward off his lily pad is pulled downward by gravity and lands on another lily pad instead of contiuing on in a straight line"
I'm confused about if an object were to stop would it be considered Newton's 1st law
 
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  • #2
First answer this: why do you wear a seatbelt?
 
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  • #3
jakeginobi said:
1. The problem statement, all variables and
given/known data
What would the best choice be:Newton's Law 1 or 2 or 3. Wearing a seatbelt and when it stops.

Homework Equations


N/A

The Attempt at a Solution


I thought the best choice would be 3 because for every action there's a reaction. I don't know any responses that fit to Newton's Law 1. I don't think it's Law 1 because objects tend to stay in motion/rest unless acted by external force, and there was an unbalanced force that caused change - or does it also imply that if an unbalance force is exerted it fits Newton's Law 1? The seat belt causes an external force and Law 1 states that the net force would be 0

One more question why would this be Newton's 1st law?
"a frog leaping upward off his lily pad is pulled downward by gravity and lands on another lily pad instead of contiuing on in a straight line"
I'm confused about if an object were to stop would it be considered Newton's 1st law
In your analysis, I don't see any consideration of Newton's 2nd law. Is your body decelerating? Is the seat belt exerting a force on your body? Have you drawn a free body diagram of your body during the time the seat belt force is acting on it?
 
  • #4
The seat belt exerts a force to stop the person from going forward.

If there is an acceleration/deceleration does it mean that it isn't Newton's 1st law?
 
  • #5
jakeginobi said:
The seat belt exerts a force to stop the person from going forward.

So, you get into your car, you fasten your seat belt and the seat belt "stops you going forward"? Really? Is that why you wear a seat belt? It's not why I wear one!
 
  • #6
jakeginobi said:
The seat belt exerts a force to stop the person from going forward.

What's wrong with going forward?
 
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Related to Which law of motion accounts for seatbelts

1. What is the first law of motion?

The first law of motion, also known as the law of inertia, states that an object at rest will remain at rest and an object in motion will remain in motion at a constant velocity unless acted upon by an external force.

2. How does the first law of motion apply to seatbelts?

The first law of motion explains why seatbelts are necessary for safety in a moving vehicle. Without a seatbelt, a passenger will continue to move at the same speed and direction as the vehicle if it suddenly stops or changes direction, potentially causing injury. The seatbelt applies an external force to the passenger, keeping them in place and preventing them from being thrown forward.

3. Does the second law of motion also apply to seatbelts?

Yes, the second law of motion, also known as the law of acceleration, is also relevant to seatbelts. This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In the case of seatbelts, the force of the passenger's body moving forward is counteracted by the force of the seatbelt, causing a decrease in acceleration and reducing the likelihood of injury.

4. Can you explain how the third law of motion relates to seatbelts?

The third law of motion, also known as the law of action and reaction, states that for every action, there is an equal and opposite reaction. In the case of seatbelts, the action is the force of the passenger's body moving forward, and the reaction is the force of the seatbelt pulling them back. This equal and opposite force helps to keep the passenger in place and prevent them from being thrown out of their seat.

5. Are there any exceptions to the laws of motion when it comes to seatbelts?

While the laws of motion generally apply to seatbelts, there are some exceptions. For example, if the vehicle is involved in a high-speed crash, the laws of motion may not be enough to prevent injury, and other factors such as airbags and crumple zones may come into play. Additionally, if the seatbelt is not properly worn or is defective, it may not be able to provide the necessary protection as outlined by the laws of motion.

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