What speed must a car travel over a hill to exert no force on the road?

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Homework Help Overview

The problem involves a car traveling over a hill and seeks to determine the speed required for the car to exert no force on the road at the crest. The context includes concepts from dynamics and circular motion, specifically involving forces acting on the car.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the relationship between centripetal force and gravitational force, questioning what it means for the normal force to be zero at the crest of the hill. There is exploration of the equations related to forces acting on the car.

Discussion Status

The discussion is ongoing, with participants examining the implications of exerting no force on the road and how that relates to the forces acting on the car. Some guidance has been offered regarding the relationships between the forces, but no consensus has been reached.

Contextual Notes

Participants are working within the constraints of the problem statement, focusing on the specific conditions at the crest of the hill and the forces involved. There is an emphasis on understanding the implications of the forces rather than deriving a solution.

beckysamis
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Homework Statement



A 915kg car goes over a hill. If the radius of this curve is 43m, how fast must the car travel so that it exerts no force on the road at the crest.


Homework Equations



Fc = mv^2/r
Fg = mg


The Attempt at a Solution



Fc = Fn+Fg
Fn=Fg
Fg=mg
=(915)(9.81)
=8976.15
Fc=?
 
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beckysamis said:
Fc = Fn+Fg
OK.
Fn=Fg
No. If there's no force on the road, what must Fn equal?
Fg=mg
=(915)(9.81)
=8976.15
OK.
 
If the car must exert no force on the road at the crest, what does that say about the force the road must exert on the car at the crest? :)
 
Doc Al said:
beckysamis said:
Fc = Fn+Fg
OK.

Should it be Fc = Fg - Fn ?

but yes anyway, it will give same result.
 

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