At time t=0, we throw a stone from the ground level straight up with a speed of 20 m/s. Ignore air drag and take g=10 m/s2.
(1) At what time, will this stone reach the highest point, and how high is it then above the ground?
(2) We now throw a second stone straight up 2 seconds after the first. How many meters above the ground is the first stone at that moment.
(3) At what speed, should we throw this second stone so as to hit the first 1s after the second stone is thrown?