

Lesson 1: Describing Motion with WordsIntroduction to the Language of Kinematics 
Lesson 5 : Free Fall and the Acceleration of GravityThe Acceleration of GravityIt was learned in the previous part of this lesson that a freefalling object is an object which is falling under the sole influence of gravity. A freefalling object has an acceleration of 9.8 m/s/s, downward (on Earth). This numerical value for the acceleration of a freefalling object is such an important value that it is given a special name. It is known as the acceleration of gravity  the acceleration for any object moving under the sole influence of gravity. A matter of fact, this quantity known as the acceleration of gravity is such an important quantity that physicists have a special symbol to denote it  the symbol g. The numerical value for the acceleration of gravity is most accurately known as 9.8 m/s/s. There are slight variations in this numerical value (to the second decimal place) which are dependent primarily upon on altitude. We will occasionally use the approximated value of 10 m/s/s in The Physics Classroom Tutorial in order to reduce the complexity of the many mathematical tasks which we will perform with this number. By so doing, we will be able to better focus on the conceptual nature of physics without too much of a sacrifice in numerical accuracy.















Observe that the velocitytime data above reveal that the object's velocity is changing by 9.8 m/s each consecutive second. That is, the freefalling object has an acceleration of approximately 9.8 m/s/s.
Another way to represent this acceleration of 9.8 m/s/s is to add numbers to our dot diagram which we saw earlier in this lesson. The velocity of the ball is seen to increase as depicted in the diagram at the right. (NOTE: The diagram is not drawn to scale  in two seconds, the object would drop considerably further than the distance from shoulder to toes.)
Lesson 5 : Free Fall and the Acceleration of Gravity
 Introduction to Free Fall
 The Acceleration of Gravity
 Representing Free Fall by Graphs
 How Fast? and How Far?
 The Big Misconception
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19962007