Answer:
20 m/s
Step-by-step explanation:
The frictional force the road exerts on the car provides the centripetal force that keeps the car in circular motion along the curve:

where
F is the centripetal force
m is the mass of the car
r is the radius of the curve
v is the speed of the car
In this problem we have:
m = 2000 kg
r = 200 m
F = 4000 N is the maximum force
Re-arranging the equation, we can calculate the maximum speed v corresponding to this force:
