The increase in the speed of a car is proportional to the additional petrol put into the engine. Is it possible to accelerate a car without putting more petrol or less petrol into the engine?
Yes, it is possible to accelerate a car without putting more petrol or less petrol into the engine. When the car, with no more or less petrol added, is moving on the curved road with a linear constant magnitude of velocity, we say that the car is accelerating since the direction of the velocity is changing continuously.