A turn of radius 20 in is banked for the vehicles going at a speed of 36 km/h. If the coefficient of static friction between the road and the tyre is 0.4, what are the possible speeds of a vehicle so that it neither slips down nor skids up?

Let us assume that the path has an inclination of θ.
There is no movement in vertical direction. So,
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If the vehicle is not to be slide up then the friction must reinforce the overall force. That means the direction must be towards mgsinθ. So, the condition will be,
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From these equations we get;
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Now we need to find tanθ
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So, the velocity will be, ![]()
For, not to skid down the condition will be
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Doing the similar calculation we will find v=54 km/hr.
So, if we move the vehicle with a speed in between 14.7 km/hr to 54 km/hr the forces will be enough to avoid skidding down and not sufficient to skid up.