Answer:
Acceleration is the rate of change of velocity with respect to time. In other words, it's how quickly an object's velocity is changing. If Bill is driving west at a constant velocity of 20 meters per second and then slows to a stop at a red light, his velocity is changing, which means he's experiencing acceleration.
In this case, when Bill slows down to a stop, his velocity is decreasing from 20 m/s to 0 m/s. The acceleration can be calculated using the formula:
Acceleration = (Change in Velocity) / Time
Since the initial velocity is 20 m/s and the final velocity is 0 m/s, the change in velocity is -20 m/s (negative because the velocity is decreasing), and the time it takes for this change to occur is the time it takes for him to slow down and stop.
The graph of acceleration over time would show a negative value (because his velocity is decreasing) that corresponds to the time it takes for him to come to a stop. After he stops, the acceleration graph would be flat at 0, as his velocity remains constant (0 m/s) while he's waiting at the red light.
If you have a description of the graphs in terms of the shape and values, I can help you identify which graph correctly shows his acceleration over time.
Step-by-step explanation: