A car rounds an unbanked curve with a radius of curvature 40 m. The coefficient of friction between the tires?


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A car rounds an unbanked curve with a radius of curvature 40 m. The coefficient of friction between the tires and the road is 0.6. What is the maximum speed the car can travel without slipping?

This is a homework question. Thank you guys for any help you can offer :)


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Answer (1):

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Use the centripetal force and Newton's Law of Motions then! We know that...

r = 40
µ_s = 0.6

It's best to draw the diagram since it helps you answer the question and understands what is going on!

Here is how the problem works if a car is on a banked curve.

F_ncos(θ) = F_nsin(θ)µ_s + mg

F_nsin(θ) + F_ncos(θ)µ_s = mv²/r

Since θ = 0, we have...

F_n = F_n * 0 * µ_s + mg

F_n * 0 + F_n * 1 * µ_s = mv²/r
F_n * µ_s = mv²/r

Since F_n = mg...

mg * µ_k = mv²/r
gµ_k = v²/r
v = √(grµ_s)

Therefore...

v = √(9.81 * 40 * 0.6)
≈ 15.3 m/s

Good luck!