Answer
Fuel consumption of a specific car for given speed.
Energy generated by wind turbine for given speed of its wings.
Revenue of a business under given production amount.
Work Step by Step
Fuel consumption of a specific car for given speed - The fuel consumption varies on the load of the car, which itself varies based on the speed of a car. Car has limit of speed, so it's fuel consumption is limited. There is a point of speed where fuel consumption reaches its maximum value.
Energy generated by wind turbine for given speed of its wings - Wind turbines work on a simple idea, faster they move, more energy they generate. But their speed is limited for a proper functioning, so it the energy generated. There is a speed when the turbines generate maximum energy it is capable of.
Revenue of a business under given production amount (and specific conditions) - Revenue of a business is depended on the production cost, that include labor, materials needed for manufacturing and several different conditions. Every business work under a specific condition, so they have some limits. For some given conditions there is a point where the revenue reaches its maximum value.