Calculating Normal Force on a Hill for a Bike and Rider - Quick HW Answers

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To calculate the normal force on a bike and rider at the top of a hill, one must consider the centripetal acceleration due to the circular motion. The combined weight of the bike and rider is 80 kg, and they are moving at a speed of 35 m/s. Using the appropriate kinetic equations in a normal-tangential coordinate system, the normal force can be determined. One participant calculated the normal force as 2418 N, indicating an upward reaction force, while another suggested a value of -849 N, which is incorrect. The correct approach emphasizes the importance of centripetal acceleration in determining the normal force.
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Homework Statement

An 80KG(bike and rider) are going over the top of a hill shaped in a circle and arch is 60m. If moving at 35m/s at top of hill what's the size of the normal force on bike and rider.



Homework Equations





The Attempt at a Solution

-849N?
 
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well, for one you're going to have centripetal acceleration so when you apply the kinetic equation (using a normal-tangential coordinate system) you'll be able to get the answer pretty easily. I got N = 2418, which unlike your answer is positive indicating an upward reaction force (assuming you're coordinate system is positive upwards)
 
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