A projectile spends 20 seconds in the air. It reaches a peak height of 8 meters. How long does it take to reach it's peak height? The projectile has a range of 80 meters. What is it's horizontal velocity?
Not possible. If it was at 8 meters, the time to fall would be
8=1/2 g t^2
and t would be sqrt 16/9.8 or about 1.3 seconds. The problem is not possible