In physics, acceleration doesn't just mean speeding up — it means any change in velocity. Since velocity is a vector (it has both speed and direction), changing direction is acceleration, even if the speed stays constant.
What's Happening in a Turn?
When a car goes around a curved corner:
The car's direction of motion is constantly changing.
This change in direction means the velocity vector is changing.
Therefore, by definition, the car is accelerating — even if the speedometer reads the same throughout the turn.
The Physics Behind It
This is called centripetal acceleration, and it's directed toward the center of the curve. It's governed by the formula: