Suppose the coefficient of static friction between the road and the tires on a car is 0.513 and the car has no negative lift. What speed will put the car on the verge of sliding as it rounds a level curve of 28.2 m radius?

Please show us what you have attempted so far. But if you’re at a total loss, here’s a hint: the centripetal acceleration of the car travelling in a circle is v^2/R, and from F=ma this tells you that the force the tires must apply to the road is F= mv^2/R. Compare that to the max force between the road and tires, due to friction (once that force is exceeded, the tires will no longer grip the road and the car starts to slide). Can you take it from here?