Circular motion with tangential acceleration

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A car starts from rest and accelerates with tangential acceleration on a flat circular track, requiring the determination of the distance traveled before skidding. The free body diagram includes normal force, gravitational force, and friction, but must also account for the static friction that provides the necessary centripetal force. The equations of motion involve relationships between force, mass, acceleration, and velocity, but the poster lacks values for acceleration and time. The key to solving the problem lies in recognizing that static friction must provide the total acceleration necessary for circular motion. The correct distance formula incorporates the coefficient of static friction, gravitational force, radius, and tangential acceleration.
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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.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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