A hot air balloon's path is modeled using the function f(x)=−x2+150

. A mine shaft elevator's path is modeled using the equation g(x)=−20x
. In both instances, the domain is time, in minutes, and the range is height, in meters. Using GeoGebra, graph the two situations. Which statement correctly interprets the graphs? (1 point)
Responses

The starting point of the balloon is higher than that of the elevator.
The starting point of the balloon is higher than that of the elevator.

Negative range values don't make sense for either scenario.
Negative range values don't make sense for either scenario.

The balloon will reach the ground before the elevator car does.
The balloon will reach the ground before the elevator car does.

Positive domain values don't make sense for either scenario.
Positive domain values don't make sense for either scenario.

1 answer

To analyze the graphs of the functions \( f(x) = -x^2 + 150 \) and \( g(x) = -20x \), let's interpret each function and its implications:

  1. Starting Points:

    • The function \( f(x) \) models the path of the hot air balloon and represents a downward-opening parabola with a maximum height of 150 meters at \( x = 0 \). Hence, the hot air balloon starts at a height of 150 meters.
    • The function \( g(x) \) models the mine shaft elevator, which decreases linearly starting from the origin (at time \( x = 0 \), the elevator’s height is 0 meters).

    This leads us to conclude that the starting point of the balloon (150 meters) is higher than that of the elevator (0 meters).

  2. Negative Range Values:

    • The height of both the balloon and the elevator can potentially reach negative values. For \( f(x) \), the range will eventually fall below 0 as the balloon descends. For \( g(x) \), the elevator's height decreases linearly, which also means it can become negative.
    • Thus, negative height values do not make sense for either situation, as both the balloon and the elevator should remain above ground (height = 0).
  3. Ground Level:

    • The balloon modeled by \( f(x) \) will hit the ground when \( f(x) = 0\). Solving \( -x^2 + 150 = 0 \) gives \( x^2 = 150 \) which means the balloon will reach the ground at approximately \( x = 12.25 \) minutes.
    • The elevator \( g(x) \) will hit the ground (height = 0) at \( g(x) = 0\), which gives \( -20x = 0 \) indicating that the elevator is at ground level starting from \( x = 0 \).
    • Therefore, the balloon will take about 12.25 minutes to reach the ground, which is longer than the elevator since it starts at the ground level.
  4. Positive Domain Values:

    • Positive time values (domain values) are sensible in both scenarios, as time cannot be negative.

Conclusion: Based on the analysis, the statement "The starting point of the balloon is higher than that of the elevator" is accurate.

Thus, the correct interpretation is:

The starting point of the balloon is higher than that of the elevator.