The document discusses static equilibrium and the center of gravity (COG) of objects. It defines static equilibrium as a condition where all forces acting on a body are balanced, causing it to remain motionless. The COG is the point where the total weight of an object is concentrated and where it balances. An object's stability depends on the position of its COG - a lower COG makes an object more stable as it is less likely to topple over. The document provides examples of stable, unstable and neutral equilibrium and factors like an object's base area and weight that influence its stability.

1. Forces in Equilibrium

4. Are forces present in static objects?

5. Static Equilibrium --- a condition in which all forces acting on a body are balanced, causing the body to remain motionless

6. Center of Gravity --- a point where the resultant force or the sum of the weights of all the particles that compose the matter are concentrated

11. Methods of locating the center of gravity For regularly shaped objects: ---- the center of gravity is at their geometric centers

12. For irregularly shaped objects ---- can be found by balancing by hanging, or by using the plumb line

14. CG

15. Why is it that the leaning tower of Pisa does not topple down?

16. For an object to balance, and not topple… support must be directly below C.O.G.

23. 2. Unstable --- when the CG is at its highest possible position

24. 3. Neutral- -- if the CG is neither lowered nor raised

25. Examples of stable objects

26. Examples of Unstable objects

27. Examples of Neutral objects

29. Which is more stable?

54. Balance two forks on the edge of the water glass using only a toothpick.

55. How does it work? The secret to this science stunt lies in your understanding of the concepts of center of gravity and stability. The center of gravity of any object is the point about which you can balance the object as if all the masses were concentrated or gathered at this point.

56. In other words, it's the point at which the object balances from left to right, front and back, and top and bottom. In your balancing fork act, the center of gravity is directly below the spot where the toothpick rests on the rim of the glass. If you look closely at your balancing fork-art, you'll notice that the fork handles are positioned below the toothpick.

57. This actually puts the center of gravity directly below the point where the toothpick is balanced (called the pivot point). Here's where it gets really strange: the center of gravity, where the forks balance front and back, left and right, top and bottom, is actually hanging in mid-air.