The leaning tower of Pisa . ... The velocity of a ball dropped from a high place increases each second by a constant amount, usually denoted by the small letter g (for gravity). ... For the falling ball in the preceding example, after t seconds that would be . ... If in addition the ball is also given at the start a horizontal velocity w , its horizontal motion continues unimpeded, advancing a distance w each second, even while the ball is falling (air resistance is now ignored). ...