A car rounding a corner at constant speed is accelerating because:

1. Acceleration is a change in velocity, and velocity carries a direction. 2. If a car turns a corner at constant speed, it is accelerating because its direction is changing. 3. Acceleration is therefore a change in either speed or direction, or both. 4. Constant speed rules out only one of those two ways to accelerate. _Source: OpenStax College Physics for AP(R) Courses 2e (CC BY 4.0), Ch 2 'Kinematics', sections 2.1-2.8_