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Homework Help: Projectile Motion Explaination

  1. Oct 29, 2005 #1
    Two spheres are launched horizontally from a 1.0m high table. Sphere A has a mass of 1.0kg and is launched with an initial speed of 5.0 m/s. Sphere B has a mass B has a mass of 0.4kg and is launched with an inital speed of 2.5 m/s.

    Compare the times for each sphere to hit the floor.
    Compare the distances that each travels from the edge of the table.

    I just need some explaination in the concept of the first question.
    I know the the equation used to find the time is [tex] t = \sqrt{ \frac {2h}{g}} [/tex] and the answer is 0.45s
    But I don't understand why the different masses and velocities don't have an effect on the time to fall.
  2. jcsd
  3. Oct 29, 2005 #2
    the same reason that if you fire a bullet horizontally and drop one at the same instant they will hit the ground at the same instant
  4. Oct 29, 2005 #3
    The initial velocity is perpendicular to the acceleration and has no effect on it, and the acceleration of gravity is independant of mass
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