A stone thrown upward at the top of the tower reaches the ground after 5 sec. A second stone is thrown down with the same speed and reaches ground in 3 sec. What is the height of the tower

Answer 1

it takes the 1st stone 2 s to reach its peak and return to the top of the tower, now going downward with the same velocity as the 2nd stone

that velocity is 9.8 m/s

when it reaches the ground, its velocity is 39.2 m/s...4 s * 9.8 m/s

its average velocity is 24.5 m/s
... (9.8 + 39.2) / 2

the distance (height) is 73.5 m
... 3 s * 24.5 m/s