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Math Help - physics

  1. #1
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    physics

    A person drops a ball in a train traveling along a straight, horizontal track at a constant velocity. What would the person in the train say about the horizontal forces acting on the ball?

    a. There are no horizontal forces acting on the ball.
    b. There is a fictitious (inertial) force acting forward.
    c. There is a fictitious (inertial) force acting backward.
    d. There is a centrifugal force.
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  2. #2
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    Re: physics

    Quote Originally Posted by Louisana1 View Post
    A person drops a ball in a train traveling along a straight, horizontal track at a constant velocity. What would the person in the train say about the horizontal forces acting on the ball?

    a. There are no horizontal forces acting on the ball.
    b. There is a fictitious (inertial) force acting forward.
    c. There is a fictitious (inertial) force acting backward.
    d. There is a centrifugal force.
    what do you think, and why?
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  3. #3
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    Re: physics

    Hmm, I can repeat my spiel about the "throwing force"... Recall the first and second Newton's laws and take into account that a train traveling at a constant velocity is an inertial reference frame, where the Newton's laws hold.
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    Re: physics

    I would say that it moves forward
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    Re: physics

    no force acting on it
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    Re: physics

    the person on the train would see the ball fall straight down from his frame of reference.
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    Re: physics

    no force would be acting on it if a person on a train would see it, but really it would move forward?
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  8. #8
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    Re: physics

    Quote Originally Posted by Louisana1 View Post
    no force would be acting on it if a person on a train would see it, but really it would move forward?
    You are right about the force. When you say "it would move forward," you mean with respect to which frame of reference: the train or the track?
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    Re: physics

    What would the person in the train say about the horizontal forces acting on the ball?
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  10. #10
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    Re: physics

    You might also ask what an observer on the ground would say about horizontal forces acting on the ball as it drop. He'd have the same answerto this as the observer on the train.
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  11. #11
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    Re: physics

    So is the correct answer (a) ??
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    Re: physics

    Perhaps if the ball on the train dangles from a string and the string is cut it is more obvious to any confused students that there is no sideways force?

    I read emakarov's Meowton post. I hope that one day I too am so confident that I'm respected that I can talk nonsense without being afraid that people will think I'm an idiot.
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  13. #13
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    Re: physics

    Quote Originally Posted by a tutor View Post
    Perhaps if the ball on the train dangles from a string and the string is cut it is more obvious to any confused students that there is no sideways force?

    I read emakarov's Meowton post. I hope that one day I too am so confident that I'm respected that I can talk nonsense without being afraid that people will think I'm an idiot.
    ^^ Me too
    It was funny..
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  14. #14
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    Re: physics

    Quote Originally Posted by puresoul View Post
    So is the correct answer (a) ??
    yes
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