Today in class exams were handed back, and many of you saw your best score yet.
Today's topic was Work (scientifically) - any time a force is used to affect an object's motion, work is done on the object. The movement must not be perpendicular to the applied force.
Examples of work were discussed, and examples where no work is done on an object.
We had a demonstration of doing work; lifting a block of wood to the table. The work that was done is its weight (the force that was applied to lift it) times the height of the table.
The unit for work is N*m, or Joule. Not coincidentally, this is the same unit as Energy. We calculated the GPE of the block of wood on the table and found the same value.
(Work <--> Energy)
Finally we discussed KE being dissipated through friction (work here being frictional force * distance an object slides until having no more KE). We related this to the marble GPE-KE lab and in some classes discussed the implications of this in an automobile - a scary idea when you start increasing velocity in the KE = 1/2 m v^2 equation.
Remember, science fair review committee Thursday after school - sign up or speak to me if interested.
Homework: (read p.154-159), p. 159#1-7, and p.881#59-65 Due WEDNESDAY
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