Comment on Wear your seatbelt

• malle_yeno@pawb.social ⁨1⁩ ⁨day⁩ ago

  So I only took one physics class and never had to do it again, so I have no clue how to think of this. But doesnt a heavier car need more force to bring it + the passengers up to velocity than a lighter vehicle?

  If that’s the case and that car crashed, then I would figure the passengers would experience more force going the opposite direction than passengers in the lighter vehicle. That seems like it’d be more dangerous, even though both sets of passengers travelled at the same speed. Am I off base?

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  • cynar@lemmy.world ⁨1⁩ ⁨day⁩ ago

    The momentum matters when you hit something. A large truck has a lot more momentum than a small car. If it hits something it needs proportionally more force to stop it. Since forces are equal and opposite, that means the hit object has to absorb more force. Basically thing of the difference between someone dropping a marble on your head from a balcony to doing the same with a bowling ball. It’s the same with a child hit by a vehicle.

    For passengers, only their mass matters. Whether you’re in a car, a truck, a train or an ocean liner, all that matters is the person’s mass and the rate of change.

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  • sugar_in_your_tea@sh.itjust.works ⁨1⁩ ⁨day⁩ ago

    Yes, you’re off base.

    The amount of force you experience has nothing to do with the vehicle you’re in, but the acceleration (positive or negative) you experience. In the case of a brake check, the only factors are starting speed, ending speed, distance, and time. It doesn’t matter if you’re increasing speed (positive acceleration) or slowing down (negative acceleration), the total force will be the same (just different directions).

    Here are some formulas:

    • acceleration = change in velocity / change in time
    • force = mass * acceleration

    In this case, the mass is your mass, since you’re the one experiencing the acceleration.

    If you’re riding a bicycle at 15mph and slam on the brakes and stop in 10 feet, you’ll feel exactly the same force as being in a massive truck going 15mph and stop in 10 feet.

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  • pineapplelover@lemmy.dbzer0.com ⁨1⁩ ⁨day⁩ ago

    If you have toy car Lamborghini that has the same 0-60 and speed of an actual Lamborghini, does it even matter?

    I once asked my physics professor if I would feel more force when breaking on a bus compared to a regular car and I believe the answer was no.

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• bamboo@lemmy.blahaj.zone ⁨1⁩ ⁨day⁩ ago

  “Weight has nothing to do with it!”

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  • Holytimes@sh.itjust.works ⁨1⁩ ⁨day⁩ ago

    Great example of the difference between the ability to read and comprehending what you read.

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  • rapchee@lemmy.world ⁨1⁩ ⁨day⁩ ago

    weight of the car

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