All planetary bodies exert a gravitational force on all objects present on their surfaces. This force is proportional to the acceleration of falling objects on their surfaces. Since the mass of the Earth is essentially constant, the acceleration due to gravity of falling objects at or near its surface is a constant. We denote it as "g" and its value is 9.81 m/s^2 (or 32.2 ft/s^2). This means that, if wind resistance is ignored, all objects regardless of their mass will fall with this same acceleration toward the ground. So mass has no bearing here. A heavy object and a light object (with similar wind resistance) dropped from the same height will fall with the same acceleration (and by extension velocity) and hit the ground at the same time. The higher a distance that the objects are dropped from, the faster velocity they will attain before hitting the ground (but the acceleration will be constant). The only reason that a feather will fall slower than a bowling ball in real life is because the feather has much more surface area and therefore friction against the atmosphere (wind resistance) than the bowling ball.