(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A blue ball is thrown upward with an initial speed of 23 m/s, from a height of 0.6 meters above the ground. 2.8 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 6.8 m/s from a height of 28.9 meters above the ground. The force of gravity due to the earth results in the balls each having a constant downward acceleration of 9.81 m/s2.

How long after the blue ball is thrown are the two balls in the air at the same height?

2. Relevant equations

v=vo+at

d=vot+1/2at^2

d=vt-1/2at^2

v^2=vo^2+2ad

d=t((vo+v)/2)

3. The attempt at a solution

Since yblue(t)=yredt

and

yred(t)=28.9+vred(t−2.8)+12a(t−2.8)2

yblue(t)=0.6+vbluet+12at2

So I tried to solve for t, but I never got the correct answer =(

So frustrating. If someone could help or even just give me a numerical answer so I can see where I went wrong that would be awesome!

[

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Kinematics Ball throwing problem. Help!

**Physics Forums | Science Articles, Homework Help, Discussion**