a projectile returns to its original height after 4.08 seconds, during which tie it travels 6.2 meters horizontally. If air resistance is ignored, what was the projectile's initial speed?

Answer 1

horizontal velocity (vh) = 6.2 m / 4.08 s

initial vertical velocity (vv)
... = (4.08 s / 2) * g

(initial speed)^2 = vh^2 + vv^2