* A car braking to a stop: When you press the brake pedal, you're applying a force that slows the car down. This slowing down is negative acceleration, as the car's velocity is decreasing.
* A ball thrown upwards: After you throw the ball, gravity acts on it, causing it to slow down as it travels upwards. This is negative acceleration as the ball's upward velocity decreases until it momentarily comes to a stop at the highest point.
* A roller coaster going down a hill then up the next: As the roller coaster goes up the second hill, its speed decreases. This is negative acceleration as the coaster's velocity is decreasing.
* An airplane landing: As the airplane prepares to land, it slows down to a safe landing speed. This decrease in speed is negative acceleration.
Key Point: Negative acceleration doesn't mean the object is necessarily moving backwards. It simply means the object is slowing down.
