Physics
posted by Lilly .
A projectile is launched horizontally with a speed of 80.0 m/s. If the projectile is launched 1.5m above the floor, how long does it take the projectile to hit the floor?

The horizontal launching speed has zero vertical component. The time to hit the ground will be the same as if it were simply dropped.
1.5 m = (1/2) g t^2
Solve for t