Which situation describes a negative acceleration?
• a swimmer moving at a constant velocity
• a runner slowing down at the end of a race
• a bicycle increasing its velocity as the rider pedals harder
• a diver jumping off a diving board and falling to the swimming pool below
• a runner slowing down at the end of a race
A runner slowing down at the end of a race describes a negative acceleration.
A negative acceleration occurs when an object's velocity decreases over time. To determine which situation involves a negative acceleration, we need to compare the given scenarios.
1. A swimmer moving at a constant velocity: This scenario describes uniform motion where the swimmer is maintaining a steady speed. Since there is no change in velocity, there is no acceleration, positive or negative.
2. A runner slowing down at the end of a race: In this case, the runner is reducing their velocity as they approach the finish line. As the runner's speed decreases, the acceleration is negative because it opposes the direction of motion.
3. A bicycle increasing its velocity as the rider pedals harder: When the rider exerts more force on the pedals, the bicycle accelerates, causing an increase in velocity. Since the velocity is increasing, the acceleration in this scenario is positive.
4. A diver jumping off a diving board and falling to the swimming pool below: As gravity pulls the diver downward, their velocity increases in the direction of the fall. Consequently, this scenario describes positive acceleration.
Therefore, the situation that describes negative acceleration is when a runner slows down at the end of a race.