![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6WADZo3sIIy5x7mwMx9arFl_orJi1WAydH6jh1FY2O2H7Ls01wib1yu3uUVDfwVHc-aO6ia1_jQo04SqTbcHpTh40F5m7vF9_ETsl1lBaT6aDjOeFjAIAQq653lMStY9M0YQizg/s320/Bouncing+ball.JPG)
This graph shows the motion of a ball held in a hand and then dropped so that it falls to the floor and repeatedly bounces. At A, it is in the hand, so it has zero velocity. As it falls, its velocity increases. At B, it hits the floor. It changes direction, but is still moving, so it has a velocity but it becomes negative. As it rises back up, it slows down due to gravity. At the top, it has velocity zero (C) before it falls again, with an increasing velocity to hit the ground at D etc. The gradient of a velocity-time graph gives you the acceleration, so here the gradient = 9.81 m/s/s/
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpmuAEDS-czxxO5ncwwEGhlTDoff-ML92RpZrEcBkRUSFCWNZgsnfRBqvB3ZDCuKaZBvWNOigiGhnWd6b7l3JlslQPNzRyRgpvtZ8bs0uxIUYzUmPRkB5I3T64gXeJSpvPfFhoMA/s320/Rocket.JPG)
This next graph is for a rocket. As it burns fuel, the thrust upwards is bigger than the weight downwards, so it accelerates. At C it runs out of fuel, so the weight starts to make it decelerate. It goes slower and slower until it stops at E, ready to fall back. E is the highest point that it reaches.