Monday, March 16, 2015

More Force Stuff

Last class, we cleared up more facts about forces and made this list:
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We all agreed that on a force diagram if the forces are equal, they should appear equal and have congruency markings.  Those forces with unequal magnitude should appear unequal in length and not have congruency markings.  We also decided that the force diagrams will only show forces acting upon an object at one specific time, even if the object is already in motion caused by a different force.  Another thing the class decided was that all the arrows should come from the "dot" or object that the forces are acting upon.  As for initial velocity for an object that was already in motion, I think we should still include a side note of it because it is useful information for if we were doing a lab and made force diagrams for different situations.  I understand overall how to draw a basic motion map now.

Thursday, March 12, 2015

Force Diagrams

Last class, we came to a consensus that in force diagrams, there are equal forces with an object pushing on the earth and the earth pushing back that result in the object staying at rest, or have a velocity of 0.  In a force diagram where the object is moving from rest, it's the same diagram as one at rest but with another force exerted by another object, such as the mallet from the bowling ball activity.  But there's one thing everyone couldn't seem to agree on: how a force diagram would look if the object was not starting at rest (already moving).  Would there be another arrow on the diagram to show it?  Would it just not be included?  The idea that made the most sense to me was to add a note stating the initial velocity to show that it would increase after being affected by whatever force was being exerted upon in the diagram because the initial velocity is useful/ necessary information, especially if you're creating graphs or motion maps from this data.