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Homework Help: Dropping a Ball in a Moving Bus

  1. Apr 22, 2007 #1
    1. The problem statement, all variables and given/known data
    A young child standing in the aisle of a parked bus tosses a ball straight up in the air and lets it drop at her feet. If instead the bus is moving at a constant speed of 30 km/h straight down the street and the child tosses the ball up in the air and lets it drop, where will the ball land? Why?
    Would the result be the same if the bus were accelerating when the ball was tossed? If the child started running down the aisle of the bus after tossing the ball? If the bus made a turn to the left while the ball was tossed? Why or why not?

    2. Relevant equations
    I don't think there are any... it's not a math-based physics course.

    3. The attempt at a solution
    Part one:
    The ball will still land by her feet, since she, the ball and the bus are all moving at a constant 30 km/h, and the horizontal component of motion for a projectile is completely independent of the vertical component of motion.
    Part two:
    The results would be the same; the ball would land in the same place. The ball is still moving at the same speed as the bus, and is unaffected by the motion of the bus.

    Is this a correct answer? Thanks so much for your help! :blushing:
  2. jcsd
  3. Apr 22, 2007 #2
    Close but no cigars. The unaccelerated case is correct.

    Get in a car or bus and do the experiment (while someone else is driving Please!). Please report back and tell us the results of your experiment and then we can help you explain what you observed.
  4. Apr 22, 2007 #3
    Oh! Of course! :rolleyes: Silly ol' me!

    If the bus were accelerating, the ball would drop behind where it previously had, because it would still be travelling at 30 km/h, and the bus would then be travelling faster... right? :redface:

    And I'll definitely do this in the car at some point, thanks for the help!
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