A bird flying horz. drops fish from 4m. Fish travels 7.9m horz. before hitting...

[ajr]

...water. Initital speed of bird? A pelican flying along a horizontal path drops a fish from a height of 4.0m. The fish travels 7.9m horizontally before hitting the water below. What was Pelican's initial speed?

[David N]

You know acceleration due to gravity is 9.8 m/s^2
Find the free fall time from 4.0 m.
During free fall the fish travels 7.9 m horizontally -- the same distance as the bird (air resistance is negligible.)

Divide the horizontal distance by the free fall time.

distance / time = speed