1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Kinematics equations with collision fo 2 balls

  1. Oct 1, 2008 #1
    1. The problem statement, all variables and given/known data
    a ball is shot straight up from the ground with speed Vo. simultaneously, a second rubber ball at height h directly above the first ball is dropped from rest
    at what height above the ground do the balls collide?asnwer should be a symbolic expression in terms of Vo and g.

    2. Relevant equations
    kinematics equations

    3. The attempt at a solution
    we can use (delta)x = Vot + 1/2 a t2 and since we know that the final positions are equal we can write this equation for the 2 balls and make them equal to each other
    but the equation of the second ball would have a x(initial) for the ball in the equation (assuming the base line is the ground).........

    can someone help me out please. Thanks in advanced
  2. jcsd
  3. Oct 1, 2008 #2


    User Avatar
    Homework Helper

    You mostly have it.
    Construct the upward equation first:
    X=Vo*t - 1/2*g*t2

    Then construct the equation from rest:
    X= h - 1/2*g*t2

    If you solve for t then you just substitute into one of the x equations for the height.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook