1. Gravity/Air Resistance

2. THINK-PAIR-SHARE – What happened if you dropped two different objects (meaning different masses) on the same planet? – Did you already know this? What experience have you had that may have taught you this? – Share with your partner.

3. YES, it is true that if you drop two objects with differing masses they will hit the ground at exactly the same time. WHY?? – According to Newton’s laws, when an object is accelerating it must have a force. For falling objects that force is gravity between the object and Earth

4. Acceleration is due to the force of gravity. The force of gravity is 9.8 meters per second per second So for every second an object is falling its velocity is increasing by 9.8 m/s/s.

5. Mass and Weight Weight is a measure of the force of gravity on an object. How did you measure weight for this activity??

6. Demonstration: – Tennis ball and a pencil PICK A GROUP OF 3 – Timer – Recorder/Observer – Dropper

7. What did you observe during the demonstration? Why? Did the two objects hit the ground at exactly the same time? Why or why not?

8. Air Resistance Experience tells you that objects with different masses do not always hit the ground at the same time. The reason is air resistance, objects are pushed up by this opposing force. Eventually the forces become balanced and the object is no longer accelerating but it is moving at a constant velocity.