L ook for the bus 53 m in front of a point directly below the edge of the ramp. The final velocity of the bus will be the vector sum of its horizontal and vertical velocities on impact. Since there is no horizontal acceleration, the velocity in this direction remains constant. There is an acceleration vertically, however. Initially, the bus has no vertical velocity, but this will obviously change.
Gravity pulls everything relentlessly toward the earth.
Once there's no more road to hold up the bus, there's nothing to keep it from accelerating down. Trebuchet Resource Site galileo Dialogue Concerning Two New Sciences .