1. 2 Mechanical Equilibrium 2.1 Force A force is a push or a pull. What is a force? Measured quantity Force SI Unit Newton Symbol N

2. 2 Mechanical Equilibrium Net Force The combination of all forces acting on an object is called the net force. 2.1 Force

3. 2 Mechanical Equilibrium An unbalanced force is needed to change an object’s state of motion. 2.1 Force A force is a push or a pull.

4. 2 Mechanical Equilibrium Balanced vs. Unbalanced Force Balanced force occurs when the net force = 0 N (the object experiences no change in motion) Unbalanced force occurs when the net force > 0 N (the object experiences a change in motion) 2.1 Force It takes an unbalanced force to change the motion of an object!

5. 2 Mechanical Equilibrium Net Force When the girl holds the rock with as much force upward as gravity pulls downward, the net force on the rock is zero. 2.1 Force Normal Force Gravity F norm = F grav

6. 2 Mechanical Equilibrium Net Force The net force depends on the magnitudes and directions of the applied forces. 2.1 Force The blue arrows are called vectors (they indicate size and direction)

7. 2 Mechanical Equilibrium Net Force The net force depends on the magnitudes and directions of the applied forces. 2.1 Force The blue arrow in the net force column is a type of vector called the resultant (5 N + 10 N = 15 N)

8. 2 Mechanical Equilibrium Net Force The net force depends on the magnitudes and directions of the applied forces. 2.1 Force

9. 2 Mechanical Equilibrium Net Force The net force depends on the magnitudes and directions of the applied forces. 2.1 Force 10 N – 5 N = net force of 5 N to the right

10. 2 Mechanical Equilibrium Net Force The net force depends on the magnitudes and directions of the applied forces. 2.1 Force

11. 2 Mechanical Equilibrium Net Force The net force depends on the magnitudes and directions of the applied forces. 2.1 Force 5 N – 5 N = net force of 0 N …which is equilibrium!

12. 2 Mechanical Equilibrium Force Vectors can be drawn to scale This vector represents a force of 60 N to the right. 2.1 Force N Vectors show magnitude (size) and direction

13. 2 Mechanical Equilibrium How can you change an object’s state of motion? 2.1 Force Apply a net force greater than zero.

14. 2 Mechanical Equilibrium Mechanics The study of energy and forces and the effect they have on bodies.

15. 2 Mechanical Equilibrium An object in mechanical equilibrium is stable, without changes in motion.

16. 2 Mechanical Equilibrium Things that are in balance with one another illustrate equilibrium. Things in mechanical equilibrium are stable, without changes of motion. The rocks are in mechanical equilibrium. http://library.thinkqu est.org/27638/leanin g.htmlhttp://library.thinkqu est.org/27638/leanin g.html

17. 2 Mechanical Equilibrium http://video.googl e.com/videosearc h?q=leaning+tow er+of+pisa&emb= 0&aq=0&oq=leani ng+tower+of+#http://video.googl e.com/videosearc h?q=leaning+tow er+of+pisa&emb= 0&aq=0&oq=leani ng+tower+of+#

18. 2 Mechanical Equilibrium

19. http://sciencefair.math.iit.edu/projects/pisa/ An object will fall if its center of mass is no longer situated within its base

20. 2 Mechanical Equilibrium http://video.googl e.com/videosearc h?q=leaning+tow er+of+pisa&emb= 0&aq=0&oq=leani ng+tower+of+#http://video.googl e.com/videosearc h?q=leaning+tow er+of+pisa&emb= 0&aq=0&oq=leani ng+tower+of+#

21. 2 Mechanical Equilibrium http://www.travelblog.org /Europe/Italy/Tuscany/Pis a/blog-403600.html