A ball is thrown upward from the ground with an initial speed of 25 m/s; at the same instant, a ball is dropped from rest from a building 15 m high. After how long will the balls be at the same height ?

g = - 9.81 m/s.s

This is high school straight line free fall motion question.

Attached is the equation I used to solve this problem.

I let the final positions of the two motions equal to each other. That gave me time of 3/5 sec.

I made origin 15 m above ground. So, ball was thrown from initial position of -15m. Ball was dropped from initial position of 0 m .

Is my answer of 3/5 sec. correct ?

motion-equation.png