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    (Original post by Kyber Ninja)
    So you're one of those guys smh

    illogical
    illogical guy right batman
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    (Original post by Kyber Ninja)
    So you're one of those guys smh

    illogical
    Not really, it seems logical to me.

    A lot of the books on mechanics and analytical dynamics take upwards as +ve most of the time.
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    (Original post by RDKGames)
    Not really, it seems logical to me.

    A lot of the books on mechanics and analytical dynamics take upwards as +ve most of the time.
    tbh i still dont get it

    sometimes s is a negative

    sometimes g is a negative

    you guys said choose which way is negative, wtf does that mean

    still confused
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    (Original post by awijdijwajiodji)
    tbh i still dont get it

    sometimes s is a negative

    sometimes g is a negative

    you guys said choose which way is negative, wtf does that mean

    still confused
    Just ask your teacher.
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    (Original post by RDKGames)
    Just ask your teacher.
    shes as thick as shreks swamp
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    (Original post by awijdijwajiodji)
    tbh i still dont get it

    sometimes s is a negative

    sometimes g is a negative

    you guys said choose which way is negative, wtf does that mean

    still confused
    If an object is falling only it makes sense to take gravity as positive.

    If an object is going upwards then it would make sense for the velocity to be positive but gravity to be negative as the gravity is opposing the direction of motion.

    A good way to see it is if an object is moving in the same direction as gravity then you can make both of them positive but if the object is moving in the opposite direction to gravity you can make velocity (and likely displacement) positive and gravity negative.
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    (Original post by AspiringUnderdog)
    If an object is falling only it makes sense to take gravity as positive.

    If an object is going upwards then it would make sense for the velocity to be positive but gravity to be negative as the gravity is opposing the direction of motion.

    A good way to see it is if an object is moving in the same direction as gravity then you can make both of them positive but if the object is moving in the opposite direction to gravity you can make velocity (and likely displacement) positive and gravity negative.
    Finally, someone who uses up as negative
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    (Original post by Kyber Ninja)
    Finally, someone who uses up as negative
    Only sometimes though.
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    (Original post by AspiringUnderdog)
    If an object is falling only it makes sense to take gravity as positive.
    How about if the object is projected upwards and you want to find the greatest height? In that situation the motion and diplacement are positive but acceleration is negative so one could argue that it makes more sense (and fewer negatives in the working) to set upwards as positive?

    Personally I like to encourage students to try taking both upwards and downwards as positive and not to stick to one rigid method.
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    (Original post by Notnek)
    How about if the object is projected upwards and you want to find the greatest height? In that situation the motion and diplacement are positive but acceleration is negative so one could argue that it makes more sense (and fewer negatives in the working) to set upwards as positive?

    Personally I like to encourage students to try taking both upwards and downwards as positive and not to stick to one rigid method.
    If it is going up and down it isn't falling only which is what I said before.

    If I have a projectile being shot up and then falling back down I will take displacement and initial velocities as positive and gravity as negative. Mainly because I haven't seen a single question where the object lands lower than the original height other than when it is "only falling". This way there are less negatives which is nicer
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    (Original post by AspiringUnderdog)
    If it is going up and down it isn't falling only which is what I said before.

    If I have a projectile being shot up and then falling back down I will take displacement and initial velocities as positive and gravity as negative. Mainly because I haven't seen a single question where the object lands lower than the original height other than when it is "only falling". This way there are less negatives which is nicer
    Agreed. I think it's up to the student to practice these types of questions and find out what they prefer. I can vary a lot depending on the question and it's hard to tell a student to always do it a certain way.
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    (Original post by AspiringUnderdog)
    Only sometimes though.
    You can take your filthy rep back then; I only want a man who consistently uses up as negative.
 
 
 
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