Supposedly going faster uses more fuel. But your getting to the place quicker. Shouldn’t you just be using the same amount of fuel as if you were driving slower and getting there later?
In: Chemistry
So the best way to explain this is to use a real example. Lets use the most obvious one and picture a journey in a car. Your fuel consumption is going to be based primarily on 4 things.
1. Distance – This is major factor in this. If you go further, you need more fuel. A shorter trip means less fuel.
2)The effectiveness of the engine consuming fuel. Different cars have different engines and not all are as good at turning the fuel into power as the others.
3) The weight of the car (including all the passengers and the fuel). The more weight you have the more energy you need to put in to get the vehicle moving. This in turn uses more fuel.
4) Drag. This is more specifically what you were asking about, as this is what causes extra fuel consumption at higher speeds. It may look like theirs nothing in the way ahead of a car, but it does actually have to move the air in its path out of the way. The faster you are going the more air you are displacing every second. As the car “pushes” the air out of the way , the air also pushes back against the car, effectively slowing it down. So you have to apply more force to counter the air moved. This again costs energy to do. and increases fuel consumption.
and just to add more to this in the case of driving. Driver behaviour changes fuel consumption. It is much much much less efficient to keep accelerating and slowing down than it is to just keep a constant speed (assuming they average to the same speed). So people who drive really fast and then keep stopping at reds are just wasting fuel. And to go even further…. most car manufacturers have and make available information about the most economic/efficient speed for their cars. Meaning they have worked out the best constant speed to keep to, to minimise fuel consumption.
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