Normal force on top of a loop?

AI Thread Summary
To calculate the minimum speed of a roller coaster at the top of a loop, the normal force is set to zero because the coaster is in a state of free fall, effectively "floating" at that point. This occurs when the gravitational force is equal to the centripetal force required to keep the coaster on its path. At this critical point, the roller coaster is vertically stationary and transitioning from ascending to descending. Understanding this concept is essential for solving the equation n + w = m*v^2/r. The discussion clarifies the relationship between forces acting on the coaster at the loop's apex.
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Say we have a roller coaster, and we want to calculate the speed the roller coaster can go at barely making the loop. Normally, the equation would be n+w=m*v^2/r, but why do we set normal equal to zero when we're solving for the minimum speed? Where does the normal come from on top of the roller coaster anyway? Thank you all so much.
 
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Hhhmmm...I am not sure I am following, but it seems to me that you already answered your own question.

What does the normal come from? It doesn't...that's why you set the normal to zero in the equation that you are solving, because if you want to calculate the point at which the roller coaster just makes it...well, at the point the coaster is "floating" and vertically stationary in midair as it is stopping from going up and getting ready to start coming down...

do I make sense?
 
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