Power = F v.
The power of a car accelerating at a = 2ms-2. Taking into account resistance forces , you can find the force of the engine without any problem. To find the power you need to find the velocity. If the velocity is increasing than the power is increasing. You need to know the specific point at which you want to find the power. If the velocity is 5 ms-1 and later 7 ms-1 than you have two different values of power eventhough the acceleration and force are constant.
