Question

A stone is tossed upward at the moment a ball is dropped from a height of 25 meters. The stone’s initial velocity is 25 m/s. At what height will the two meet? In how many seconds.

Answer 1

$x_1=25-\frac{gt^2}{2}$

$x_2=v_0t-\frac{gt^2}{2}$

$x_1=x_2\to25=v_0t\to t=25/25=1(s)$

$h=25-9.81\cdot1^2/2=20(m)$

Answer. $h=20(m)$ and $t=1(s)$ .