Find the minimum constant power needed. When you accelerate a car or boat from rest at full throttle, it will not increase speed without limit, it will eventually settle at a constant speed. This speed is the terminal speed for the object, and it depends on the available power from the engine and the aerodynamic drag. The drag force at low speeds is proportional to the speed. At higher speeds the drag is proportional to the square of the speed, then the 4 th power etc.
C D is the drag coefficient produced by the shape of the car.
For most cars C D lies between 0.2 and 0.5. Other times, it is undesirable and just increases costs. The efficiency of a machine measures the percentage of useful power out to the total power in. A 50kg woman climbs a mountain 3000m high. When objects collide they exert equal action-reaction forces on each as they deform.