We calculate the distance that is traveled by the bill for 0.25s through the equation,
  d = Vot + 0.5gt²
Substituting the known values to the equation,
  d = (0.5)(9.8 m/s²)(0.25 s)²
   d = 0.30625 m
This is equal to 30.625 cm. Hence, the length of the bill should be 30.625 cm.
ANSWER: 30.625 cm