Quote:
Originally Posted by maanma
Speeding up slower (longer in time) will save energy. Doubling time is halving the energy needed.
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Quote:
Originally Posted by Isaac Zachary
That's incorrect. From a physical standpoint it's the same amount of energy to accelerate to a certain speed whether you do so over a long period of time or suddenly accelerate within less than a second to your desired speed.
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It is a little more complicated than that. In a frictionless environment the rate of acceleration does not matter, but in the real world the faster accelerating car averages a higher speed and therefore encounters more wind resistance throughout its trip.
Example:
Car A accelerates from 0-60mph slowly over the course of 2 miles. Car B accelerates more briskly from 0-60 mph over 1/4 mile and then travels steadily at 60mph for the remaining 1 3/4 mile.
Technically they both expended the same amount of energy *accelerating* to 60 but car B averaged a higher speed over the 2 miles and therefore expended more energy overcoming wind & rolling resistance.
Of course it still may be that the engine is so much less efficient at light loads that you still burn less fuel consuming more total energy by accelerating briskly. This is true for my Prius - for years I wasted gas (and time) accelerating gingerly whereas I now accelerate right up to the "power" zone threshold and still use less gas for the trip.