Example: Throwing a Ball :                                                                                       A ball is thrown straight up, from 3 m above the ground, with a velocity of 14 m/s. When does it hit the ground?                                                                                                                                                                                                The height starts at 3 m: 3It travels upwards at 14 meters per second (14 m/s): 14tGravity pulls it down, changing its speed by about 5 m/s per second (5 m/s2): −5t2(Note for the enthusiastic: the -5t2 is simplified from -(½)at2 with a=9.81 m/s2)