2. Writing prompt: 10/24/06 If you sit in my rolley chair and push off the wall with your feet, which way will you move? Explain why this happens.

3. Force and Work Newton’s Third

4. Work We said before WORK and ENERGY are pretty much the SAME THING Work is equal to the energy done

5. Work So, if you raise a 10 kg mass up 1 meter in the air, the work you put into raising it, gives it its potential energy. Potential Energy = m x g x h = 10 x 9.8 x 1 =98 Joules That means your arm put 98 Joules of work into that mass

6. Work QUESTION: How much work do the legs of a 50 kg person do to jump 1 meter in the air? ANSWER: Work = Energy = m x g x h =50 x 9.8 x 1 =490 OR about 500 Joules

7. Work Work is ALSO related to FORCE Work is equal to the force used to move an object times the distance the object moved Work = Force x distance OR W = F d

8. Work W = F d QUESTION: How much work is done to lift a 10 N box 2 meters? ANSWER: W = F x d = 10 X 2 = 20 Joules (remember 1 Joule = 1 Nm “Newton meter”)

9. Work W = F d QUESTION: How much work is done if you push a box with 45 N for 3 meters? ANSWER: W = F x d = 45 X 3 = 135 Joules (remember 1 Joule = 1 Nm “Newton meter”)

10. Newton’s 3 rd law Demo: book on a table, why doesn’t it fall? Table pushes on the book with the SAME force that the book pushes on the table

11. Newton’s 3 rd law Newton’s 3 rd law: Every action has an equal and opposite reaction. OR For every force applied to an object there is an equal force applied back in the other direction

12. Newton’s 3 rd law So if you get mad and PUNCH A WALL, it hurts YOU because the wall hits you with the same force you hit it with!!!! Don’t punch walls…

13. Newton’s 3 rd law QUESTION: If you weight 500 N and you stand still on the ground, how much force does the ground push on you? ANSWER: With the SAME FORCE, 500N

14. Newton’s 3 rd law QUESTION: If you punch a wall with 75 N of force, how hard does the wall hit you? ANSWER: With the SAME FORCE, 75N

15. Newton’s 3 rd law QUESTION: If you punch a wall towards the right, what direction does the wall hit you? ANSWER: in the OPPOSITE DIRECTION, to the LEFT!

16. Newton’s 3 rd law Let’s try an activity that incorporates work and force and Newton’s 3 rd law YAYYYYYY!!!!!!!!