Option 2

Choreographed Fountains Activity: Independent Work

The image you selected to reach this worksheet was of the Magic Fountain of Montjuic in Barcelona, Spain.
Imagine you are a fountain designer and you need to know how different speed motors will affect the water’s projected height and time in the air. You have various motor speed options but need to choose the one that most closely meets the client’s height request of 690 feet. Your job is to determine which motor speed is the best choice. In all cases, you will use the projectile formula
y = –16x2+ vx + s, with starting height of 0 (s = 0).

Motor A Speed
190 feet per second

Motor B Speed
210 feet per second

Motor C Speed
230 feet per second

  1. Substitute the data provided for speed (v) and starting heights (s) into their proper positions in the formula
    y = –16x2+ vx + s and write the equation corresponding with each motor in the space provided below.
    Then identify the a, b, and c values for each where indicated. (6 points total, 2 points each)

The equation for motor A is:
a =
b =
c =
The equation for motor B is:
a =
b =
c =
The equation for motor C is:
a =
b =
c =

  1. Given that the total variation in speed from motor A to motor C is 40 feet per second, take a guess as to how varied the heights of water from the tallest to the shortest will be (in feet). (1 point)

My guess is that the variation of water height from the tallest to the shortest will be _____ feet.

  1. Use the graphing technology of your choice to graph the equation for each motor. Set rounding to 5 places. Save a copy of each graph and paste them here or attach them to the assignment. (You will be using them
    to find the vertex and x-intercepts shortly so don’t close them yet.) (15 points total, 5 points each graph)
  2. What is the formula for locating the x-coordinate of the vertex? (1 point)
  3. Go back to each motor's graph file and find the vertex coordinates. Then report them below.
    (9 points total, 3 points each)

Motor A Vertex coordinates:

Motor B Vertex coordinates:

Motor C Vertex coordinates:

  1. What is the actual range in height from the tallest to the shortest (use the appropriate heights rounded to
    the nearest foot)? (2 points)

The tallest reaches a height of approximately

The shortest reaches a height of approximately –

The difference, or actual range, is approximately

  1. What is the difference between your earlier guess and the actual difference (see #2)? (1 point)
  2. What did you learn about speed and its affect on distance from the above comparison? (2 points)
  3. Recall that your client has made a height request of 690 feet. Which motor brings you closest to that request? (1 point)
    ΟMotor AΟMotor BΟMotor C
  4. Now, in order to synchronize the neighboring fountain head to begin as soon as this one returns to the ground, you need to determine the time the water from this motor is in the air. (5 points)

Using your graphing tool, find the x-intercepts for the chosen motor.

Save a copy of this motor’s final graph and paste it here or attach it to the assignment.

How many seconds does it take for the water from this motor to return to the ground? (2 points)