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      03-01-2011, 03:39 AM   #310
swamp2
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Drives: E92 M3
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Quote:
Originally Posted by Dodge2Dub View Post
It does make sense and I understand the example of adding a passenger vs. being a lonely driver...but...if you change the mass of an object (wheel) that you want to rotate (we'll say decrease it) against a surface, then it becomes easier to rotate it (less force). So, doesn't it stand to reason that if less force is needed to rotate that object ,the translation of applying the same input power is that the object (wheel) will spin faster (increased acceleration)? If so, then if we draw a line on the ground, the power measured when the vehicle crosses over that line with the heavier rotating object (wheel) will be less than the power measured when the vehicle crosses over that line with the lighter object (wheel). Essentially, you are at a higher RPM when you cross the line with the lighter wheel (screw the object reference) then you were with the heavier wheel.
You are going around in a circle here. I can see why you might think this way. There are subtleties here. Just think back to the simple case of a "block" moving on a frictionless surface under some force (not a rotating drive wheel, just a simple directed constant force for simplicity). You must distinguish between the force and the mass. Changing one does not change the other but BOTH can change the acceleration.

Just because something accelerates faster does not imply it must have a larger force applied to it.

Quote:
Originally Posted by Dodge2Dub View Post
Are the e90 meets in Clairemont on Wednesdays? If so, I never know which Wednesday is a meet day (I believe it's every other Wednesday).
I don't go often either but they are something like every other week. I can't seem to locate the thread on it with any recent activity... I would like to go to one again sometime soon.
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