# A circular curve of highway is designed for traffic moving at 92 km/h. When assumed the traffic consists of cars without negative lift ?

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(a) If the radius of the curve is 150 m, what is the correct angle of banking of the road? (b) If the curve were not banked, what would be the minimum coefficient of friction between tires and road that would keep traffic from skidding out of the turn when traveling at 92 km/h?

(a) If the radius of the curve is 150 m, what is the correct angle of banking of the road? (b) If the curve were not banked, what would be the minimum coefficient of friction between tires and road that would keep traffic from skidding out of the turn when traveling at 92 km/h?

##### 1 Answer

(a)

(b)

#### Explanation:

(a) In the figure above

Let

We know that while in circular motion the centripetal force acting on the car

And force due to friction is given as

Assuming car to be situated at the origin, Force equations in the

For designing of banking angle of the curved roads, worst case is considered.

Very low values of

Above equations reduce to

Dividing first with second we obtain

or

Given

Inserting all values in above expression

(b) If curves are not banked, implies that

Insert value of

We observe that this is equal to value of