Circular motion with tangential acceleration

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Homework Help Overview

The problem involves a car moving with tangential acceleration along a flat circular track, where the goal is to determine the total distance traveled before skidding occurs. The context includes concepts from circular motion and friction.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to analyze the forces acting on the car using a free body diagram and considers the relationship between tangential acceleration and distance traveled. Some participants question the completeness of the free body diagram, particularly regarding the role of friction.

Discussion Status

The discussion is ongoing, with participants providing hints and prompting the original poster to think critically about the forces involved in circular motion. There is no explicit consensus on the correct approach, and multiple interpretations of the problem are being explored.

Contextual Notes

Participants note the importance of static friction in providing the necessary centripetal acceleration, and there are indications that the original poster may be missing key elements in their analysis.

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A car is initially at rest. It starts mvoing with tangential acceleration a_tan along a flat circular track of radius r. If the coefficient of static friction is mu, determine the total distance traveled by the car before it skids off the track.

This is what I did.

I drew the free body diagram with normal force point up, mg pointing down, and f point right, and acceleration (not on the diagram) is pointing left towards the center. Is this the correct diagram?

I know N=mg

and

F = ma
F = m (v^2)/r

so v=SQRT(Fr/m)

I know d = (1/2)at^2

Where do I go from here to find the distance. I don't have acceleration and time.
 
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In your free body diagram, you are missing something that relates to the friction...
 
Just think about which is the force that keeps the car in circular motion.
(The answer is d = mu*g*r/2a.)
 
aster said:
Just think about which is the force that keeps the car in circular motion.
(The answer is d = mu*g*r/2a.)
Please DO NOT provide answers--instead, help the poster do their own work.

In any case, that answer is incorrect. Hint: Static friction must provide the total acceleration.
 

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