Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dynamics Question.

  1. Mar 8, 2006 #1
    I am having difficulties understanding what situation would give a ball a larger velocity.

    The first situation is a ball is floating infront of you and you hit it with your baseball bat with a given force, and direction.

    The second situation is that the same ball is coming towards you horizontally ( it already has a non zero velocity) and you hit it with the same magnitude for force and the same direction.

    I am having difficulites understanding which ball would have a higher velocity, and travel the farthest after being hit. I am thinking its the one that is coming to me horizontally with an intial velocity because the Fnet would be bigger since the baseball bat contributes to the force on the ball plus the reaction force of the bat to the action force of the ball on the bat... It does have to do with Newtons laws doesn't it?
  2. jcsd
  3. Mar 8, 2006 #2
    hmmmm.... (assuming this problem is "in space")

    providing there is a zero acceleration on both balls I dont think it matters that one is moving or not

    I would think the balls would go at the same velocity if they were hit by the same force
    Last edited: Mar 9, 2006
  4. Mar 9, 2006 #3
    well a confusing quesion. difficult to answer.

    under real conditions, the ball coming your way will have a higher acceleration than the other one. the reaon being that there would be the velocity due to the new force as well as due to the bouncing back of the ball from the bat.
  5. Mar 9, 2006 #4
    Answering this question in a "real world" setting would be very very difficult. You would have to answer to gravity and wind resistance.

    In space though, just because a ball is moving does not mean that it has an acceleration of any positive or negative value.

    assuming it is moving at a constant velocity when you hit it with your bat, there is only one force and that is the force of the bat telling the ball to go in direction X

    the ball at rest (assuming there are no forces that are keeping it at rest acting upon it) has a zero acceleration, and when struck by the bat there is only one force telling the ball to go in direction X

    If both balls (no forces acting upon them) were hit with the same force in the same direction, then both balls have the same net force in the same direction...they should travel at the same velocity.
  6. Mar 9, 2006 #5
    Ya pretend they are in space. One ball is completly still while the other has a horizontal constant velocity that is heading towards the bat, and they are both struck with the same force and direction by the bat. Which one gains a higher velocity?

    AMF8 How sure are you about your answer?
    Last edited: Mar 9, 2006
  7. Mar 9, 2006 #6
    It seems to make sense....at least to me

    It would be nice if one of the guru's would help us out
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook