Acceleration is defined as a change in speed over time, as we all learned in high school. Getting a little more technical, acceliration is an increase in speed; a decrease in speed is called “deceleration” (or, for those with a high-school physics mind, “negative acceleration”). In your schoolbook, you probably wrote something like “accelleration is measured in metres per second squared.” However, if you’re considering a car, when you think about acceleration, you probably find metres per second squared rather hard to visualise. It’s easier to consider a rate of change in speed. Usually, figures defining a car’s acceleration are calculated by timing how long it takes the car to go from a standstill (zero) to a speed that is approximately the open road legal maximum. In metrics, this is usually 0–100 km/hr, and in imperial figures, acceleration figures consider the 0–62 mph/hr time. In general, a car that can do this in under 10 seconds has a good rate of acceleration. Sports cars have acceleration figures that are even better – some can go from 0–100 in 5 seconds or less.

Some additional facts about acceleration:

Some cars are designed to have a better rate of acceleration in the 80–120 km/hr range than they do in the 0–100 range (example: Saab 9000C). Having the acceleration peaking in this range makes the car very nimble when overtaking.

Only the top-of-the-range sports cars can match the acceleration of a cheetah: this animal can go from 0–100 km/hr in three seconds.<
We hope that helps answer the question ‘What is What is Acceleration?’!

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