Why do cars ads tell how fast a car accelerates?

Answer 1

Astute question since we are not Supposed to speed! lol. Ok, when cars need to boast efficiency to compete in an energy efficient market, one assumes that power will be anemic at best and not a fun car to drive. We ARE all after all, wannabe race drives yes? lol. Manufacturers have the difficult line to walk to state about , and more unlikely produce, a car that gets 40 Mpg and does 0-60mph in less than 6 seconds without turning 8000 rpm (short engine life). As loosely couple to a thread of truth as they can, you will see ads that most engineers and car enthusiasts will smirk over claiming that car X can do both. It does boil down to physics in teh end..

Weight, parasitic drag, mechanical frictions, rolling resistance, rate of acceleration, time to speed of test, moisture content, barometric pressure, air density, temperature etc. = horsepower needed and illustrate some of the many losses depending on the machine used. Lost more losses when the efficiency of the drive-train and engine comes under measurement.

Then fuel energy content per unit and the number of units required to produce one horsepower times the above required horsepower needed.

So.. 0-60Mph in 3.5 seconds while producing a fuel efficiency of 40mpg at the same time and propelling a 2,500lb car is unlikely to happen in e the very next few seconds. ;-)