I'm sure this is an easy question but I just can't seem to understand wich equations I need to use. A ball is thrown vertically upward with an initial speed of 11m/s. One second later, a stone is thrown veritcally upward with an initial speed of 25 m/s. Find the time it takes the stone to to catch up with the ball. So right now I have for the ball: a= -9.80 m/s^2 initial V=11m/s initial y=0 t=t2-1 and for the stone a=-9.80m/s^2 initial V=25m/s initial y=0 t=? So the way I was thinking is that the question is asking at what time the displacements are equal so I thought the equation I am supposed to use is (V^2-iV^2)/2a=(V^2-iV^2)/2a and solve for the V. This doesn't seem to work. Am I on the right track or just totally way off base? Any help or hints would be appreciated. Thanks.