3-17

On Tuesday, March 17 Mr. Manning's Physics class was shortened because of PSSA's. In this amazingly interesting class period we studied the topic of Center of Mass (or gravity). It was noted that these two terms can be differentiated between by considering the mass and weight of an object. If weight is part of the system, then we are dealing with Center of Gravity. If weight is absent, the we are dealing with the Center of mass. The center of mass is defined as the average position at which the mass is evenly distributed.

-An extra credit opportunity was given and is due on Monday, March 23rd. The assignment is to make two irregular shapes and find the center of mass on them. This can be done by attatching a plumbob and a string to a corner of the irregular shape and drawing a straight line down its path. Then attach the plumbob and string to a different corner and do the same thing. Where these two lines intersect is the center of mass of that object. Two irregular shapes along with the location of their center of masses is required for the extra credit.

When designing a structure, the center of mass is an important idea to keep in mind. For a stable structure the center of mass must above above the base of the structure. If the center of mass falls within the base of the object it is in stable equilibrium.





In the case of the boomerang, the center of gravity falls outside the boomerang itself.