1. A car speeding up: When a car accelerates from a stoplight, its speed increases, meaning it is accelerating. The change in speed over time is the definition of acceleration.
2. A ball thrown upwards: Even though the ball slows down as it travels upwards, it is still accelerating. This is because the force of gravity is constantly acting on the ball, pulling it downwards. Since the ball's velocity is changing (decreasing), it's accelerating, even though the direction of the acceleration is opposite to the direction of motion.
