Final answer:
The ideal speed for making a turn on a curve depends on the radius of the curve and the friction between the tires and the road surface.
Step-by-step explanation:
The ideal speed for making a turn on a curve depends on the radius of the curve and the friction between the tires and the road surface. When there is no friction available, the maximum safe speed at which a vehicle can turn is determined by the centripetal force required to keep the vehicle on the curve. This force is provided by the horizontal component of the net external force acting on the vehicle.
To calculate the ideal speed, you can use the following formula:
Ideal Speed = sqrt(radius * net external force)
In the given example, you are asked to determine the ideal banking angle for a gentle turn with a radius of 1.20 km and a speed limit of 105 km/h. Assuming everyone travels at the limit, you can calculate the ideal speed using the formula above. Once you have the ideal speed, you can determine the banking angle using the relationship between speed, radius, and banking angle.