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[bachikarn]

A banked circular highway curve is designed for traffic moving at 65 km/h. The radius of the curve is 189 m. Traffic is moving along the highway at 35 km/h on a rainy day. What is the minimum coefficient of friction between tires and road that will allow cars to negotiate the turn without sliding off the road?

Any help would be most appreciated.

 

[ToyMachine228]

God I just took Physics last year so I should be able to do this, but no dice. Sorry man. I always hated the math part of physics. The concepts are really cool and interesting but the math sucks.

 

[truffleshuffle83]

cefficient of friction is based on normal forceright??? dont you need to know something like say the mass of the car??

 

[Wellington]

Damn I forget exactly how to do this.

mv²/r = mgc (c for coefficient of static friction)

The mass of the car cancels on both sides, you have velocity and the radius, gravity is a known, bingo-bango:

v²/(rg) = c

Don't quote me on it though, check your physics book. I was always shitty at circular motion problems.

Where's jinx when you need him?

 

[Kangu]

Wellington's got it.

That problem sure has a lot of useless info, though. Considering they make a point of telling you the turn is banked that would have an effect on how you calculate the normal force, but they don't even give you the angle so...yeah.

 

[truffleshuffle83]

yeah that sounds right, i forgot about the other equation and the masses canceling.