A projectile is launched straight up in the air. Its height (in feet) t seconds after launch is given by the function f(t)= - 16t² +423t+6. Find its height when it is falling at 269 feet/second. C... Its height is If necessary, round to two decimal places. Do not include units.

Calculus: Early Transcendentals
8th Edition
ISBN:9781285741550
Author:James Stewart
Publisher:James Stewart
Chapter1: Functions And Models
Section: Chapter Questions
Problem 1RCC: (a) What is a function? What are its domain and range? (b) What is the graph of a function? (c) How...
icon
Related questions
Question
100%
Help
### Projectile Motion Problem

A projectile is launched straight up in the air. Its height (in feet) \( t \) seconds after the launch is given by the function:

\[ f(t) = -16t^2 + 423t + 6 \]

Find its height when it is falling at 269 feet/second.

---

#### Solution:

We'll first need to determine at what time \( t \) the velocity of the projectile is \( -269 \) feet/second (negative because it is falling).

To do that, we differentiate the height function with respect to \( t \) to find the velocity function:

\[ f'(t) = \frac{d}{dt} (-16t^2 + 423t + 6) \]

\[ f'(t) = -32t + 423 \]

Now, set the velocity equal to \(-269\) feet/second and solve for \( t \):

\[ -32t + 423 = -269 \]

Rearrange to solve for \( t \):

\[ -32t = -269 - 423 \]

\[ -32t = -692 \]

\[ t = \frac{-692}{-32} \]

\[ t = 21.625 \text{ seconds} \]

Now, substitute \( t = 21.625 \) back into the original height function to find the height at this time:

\[ f(21.625) = -16(21.625)^2 + 423(21.625) + 6 \]

Calculate the value:

\[ f(21.625) = -16(467.640625) + 9142.875 + 6 \]

\[ f(21.625) = -7482.25 + 9142.875 + 6 \]

\[ f(21.625) = 1666.625 + 6 \]

\[ f(21.625) = 1666.63 \]

Therefore, the height of the projectile when it is falling at 269 feet/second is approximately \( 1666.63 \) feet (rounded to two decimal places).

**Final Answer:**

Its height is \( 1666.63 \)

> Please note:  If necessary, round to two decimal places. Do not include units in the answer.
Transcribed Image Text:### Projectile Motion Problem A projectile is launched straight up in the air. Its height (in feet) \( t \) seconds after the launch is given by the function: \[ f(t) = -16t^2 + 423t + 6 \] Find its height when it is falling at 269 feet/second. --- #### Solution: We'll first need to determine at what time \( t \) the velocity of the projectile is \( -269 \) feet/second (negative because it is falling). To do that, we differentiate the height function with respect to \( t \) to find the velocity function: \[ f'(t) = \frac{d}{dt} (-16t^2 + 423t + 6) \] \[ f'(t) = -32t + 423 \] Now, set the velocity equal to \(-269\) feet/second and solve for \( t \): \[ -32t + 423 = -269 \] Rearrange to solve for \( t \): \[ -32t = -269 - 423 \] \[ -32t = -692 \] \[ t = \frac{-692}{-32} \] \[ t = 21.625 \text{ seconds} \] Now, substitute \( t = 21.625 \) back into the original height function to find the height at this time: \[ f(21.625) = -16(21.625)^2 + 423(21.625) + 6 \] Calculate the value: \[ f(21.625) = -16(467.640625) + 9142.875 + 6 \] \[ f(21.625) = -7482.25 + 9142.875 + 6 \] \[ f(21.625) = 1666.625 + 6 \] \[ f(21.625) = 1666.63 \] Therefore, the height of the projectile when it is falling at 269 feet/second is approximately \( 1666.63 \) feet (rounded to two decimal places). **Final Answer:** Its height is \( 1666.63 \) > Please note: If necessary, round to two decimal places. Do not include units in the answer.
Expert Solution
steps

Step by step

Solved in 2 steps

Blurred answer
Recommended textbooks for you
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781285741550
Author:
James Stewart
Publisher:
Cengage Learning
Thomas' Calculus (14th Edition)
Thomas' Calculus (14th Edition)
Calculus
ISBN:
9780134438986
Author:
Joel R. Hass, Christopher E. Heil, Maurice D. Weir
Publisher:
PEARSON
Calculus: Early Transcendentals (3rd Edition)
Calculus: Early Transcendentals (3rd Edition)
Calculus
ISBN:
9780134763644
Author:
William L. Briggs, Lyle Cochran, Bernard Gillett, Eric Schulz
Publisher:
PEARSON
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781319050740
Author:
Jon Rogawski, Colin Adams, Robert Franzosa
Publisher:
W. H. Freeman
Precalculus
Precalculus
Calculus
ISBN:
9780135189405
Author:
Michael Sullivan
Publisher:
PEARSON
Calculus: Early Transcendental Functions
Calculus: Early Transcendental Functions
Calculus
ISBN:
9781337552516
Author:
Ron Larson, Bruce H. Edwards
Publisher:
Cengage Learning