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Really basic velocity question

  1. Jul 18, 2014 #1
    You throw a rock upward. The rock is moving upward, but it is slowing down. If we define the ground as the origin, the position of the rock is___ and the velocity of the rock is___.

    I said that they are both positive because the rock is going up, and even though it is slowing down, it is still going up so the velocity is positive. Is my reasoning correct?
  2. jcsd
  3. Jul 18, 2014 #2


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    I think it's looking for either an "increasing" or "decreasing" (not a "positive" or "negative")
  4. Jul 18, 2014 #3
    The options show positive and negative.

    I think it does make sense though, because the ball is in a positive direction relative to the ground, and the velocity is upwards, but I'm not completely sure.
  5. Jul 18, 2014 #4


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    They said the ground was the origin, but they didn't say which direction (up or down) was positive.

    Your answers and reasoning are correct, but the problem really should have stated which direction is the positive direction.
  6. Jul 18, 2014 #5
    Ah I see. Thanks!
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