Centripetal Acceleration of bicyclist

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Homework Help Overview

The problem involves a bicyclist traveling in a circular path, requiring the calculation of forces related to centripetal acceleration, specifically the force of friction and the net force from the road. The context is centered around concepts of circular motion and forces acting on an object in motion.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the forces acting on the bicycle, including the net force calculated by the original poster and the distinction between net force and the force of friction. Questions arise about the nature of the forces exerted by the road and the relationship between the bicycle and the road.

Discussion Status

The discussion is ongoing, with participants exploring the definitions and distinctions between different forces acting on the bicycle. Some guidance has been offered regarding the need to consider vertical and horizontal forces separately, and there is an acknowledgment of the original poster's calculations, though clarity on the specific forces is still being sought.

Contextual Notes

Participants are navigating potential confusion between net force and frictional force, as well as the implications of the forces acting on the bicycle from both the road and gravity. There is mention of an answer sheet, but its contents are not fully disclosed in the discussion.

sylenteck0
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Homework Statement


A bicyclist travels in a circle of radius 25.0m at a constant speed of 9.00 m/s. The bicycle-rider mass is 85.0 kg. Calculate the magnitudes of a) the force of friction on the bicycle from the road and b) the net force on the bicycle from the road.


Homework Equations


F=ma
m(v^2/r)


The Attempt at a Solution


I plugged in the numbers for the force formula and got 275.4 N, I'm assuming that's the net force as its the centripetal force.

Im unsure how to find the force of the friction however. Any suggestions? (On that note, did I confuse the two?

-Thanks in advance
 
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Start by listing all the forces acting on the bicycle: name them and indicate their direction.

You did calculate the net force (assuming your arithmetic is correct), but the question asks for the net force from the road, which is not the same thing.
 
Ah, so what I found was the force of the bicycle on the road?

So, the net force on the bicycle on the road would be the reactive force from gravity, making it 9.8 x 85.0 kg, right? (Which is 833N)
 
sylenteck0 said:
Ah, so what I found was the force of the bicycle on the road?
What you found was the net force on the bicycle due to all forces, not just from the road.

What forces does the road exert on the bicycle? (Consider vertical and horizontal forces separately.)
 
According to the answer sheet, the answers I got are correct, but I'll get on thinking about that :)
 
sylenteck0 said:
According to the answer sheet, the answers I got are correct, but I'll get on thinking about that :)
How did you answer the questions? You've shown your calculation of the net force on the bicycle. That is one of the answers, but which one? :wink:

sylenteck0 said:
So, the net force on the bicycle on the road would be the reactive force from gravity, making it 9.8 x 85.0 kg, right? (Which is 833N)
That's the normal component of the force the road exerts on the bicycle, not the net force.

For your own clarity, I'd still recommend listing the forces acting on the bicycle and their direction.

Just curious what the answer sheet says.
 

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