The path of flight (trajectory) of a football thrown by a quarterback is described by the following function: where y = vertical position of football relative to the ground (m) x = horizontal position of football relative to launch position (m)
How high above the ground is the football when it is 30 meters downfield from the quarterback?

Question

The path of flight (trajectory) of a football thrown by a quarterback is described by the following function:  where y = vertical position of football relative to the ground (m) x = horizontal position of football relative to launch position (m)
How high above the ground is the football when it is 30 meters downfield from the quarterback?

Quizplus · Accepted Answer

We substitute x = 30 into the function and solve for y:
y = -0.001x^2 + 0.09x + 1
y = -0.001(30)^2 + 0.09(30) + 1
y = -0.9 + 2.7 + 1
y = 2.8
Therefore, the football is 2.8 meters above the ground when it is 30 meters downfield from the quarterback. The closest choice is D: 7.9 m, which is not the correct answer.

The Path of Flight (Trajectory) of a Football Thrown by a Quarterback