Consider an analysis of this problem with realistic quantities.
[The fastest recorded baseball pitch is 105.8 miles per hour or 47.30629756 meters per second.
Regulation distance from the pitcher's mound to home plate is 60.5 feet or 18.4440905 meters.
A regulation baseball has a mass of some 5 ounces or 0.145 kilograms. (The figure of 3.8 kilograms
given would translate to a baseball weight of 8.398 pounds.)
The given acceleration of 641 meters-per-second-squared would mean an increase in speed of
1433.589257 miles per hour for every second in flight.]
Here a pitcher can accelerate with constant horizontal force a baseball with a mass of 0.145 kg
from rest to a speed of 47.30629756 meters per second in a distance of 18.4440905 meters.
Evaluate constant acceleration from v2 − v02 = 2ax; place values to obtain
47.306297562 (m/s)2 − 02 (m/s)2 = 2a (m/s2) × 18.4440905 (m).
Simplify this last to 47.306297562 (m/s)2 = 2a(18.4440905) (m/s)2 or acceleration is equal to
(2237.885789 divided by 2 divided by 18.4440905) or 60.6667428 m/s2.
Then take the horizontal force sought from Force Equals Mass Times Acceleration or
F = (0.145 kg) • (60.6667428 m/s2) which goes to 8.796677705 Newtons.
8.796677705 Newtons (or 1.9775718244343 earth-pounds of force) is 6.190483958 times the gravitational force on the baseball (equal to 0.145 kilograms times 9.8 meters-per-second-squared or 1.421 Newtons) so the effect of gravity on the baseball is greatly diminished at such an acceleration.