Is constant speed means zero acceleration

Porque crees que el agua no podia subir mas de 10 m de altura con ese tipo de bomba

An object is dropped from a tower, 400 ft above the ground. the object's height above ground t seconds after the fall is s(t)equals400 minus 16 t squared. determine the velocity and acceleration of the object the moment it reaches the ground. the velocity of the object the moment it reaches the ground is nothing ft/s.

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?