Westonci.ca is the Q&A platform that connects you with experts who provide accurate and detailed answers. Ask your questions and receive accurate answers from professionals with extensive experience in various fields on our platform. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields.

The height, [tex]$h$[/tex], in feet of a piece of cloth tied to a waterwheel in relation to sea level can be modeled by the equation [tex]$h = 15 \cos \left(\frac{\pi}{20} t\right)$[/tex].

How long does it take for the waterwheel to complete one full revolution?

A. 5 seconds
B. 10 seconds
C. 20 seconds
D. 40 seconds


Sagot :

Let's start by examining the height equation for the piece of cloth tied to a waterwheel in relation to sea level:

[tex]\[ h = 15 \cos \left(\frac{\pi}{20} t\right) \][/tex]

where [tex]\( h \)[/tex] is the height in feet and [tex]\( t \)[/tex] is the time in seconds.

We are tasked with determining the values of [tex]\( h \)[/tex] at specific times: 5 seconds, 10 seconds, 20 seconds, and 40 seconds.

Steps to solve for [tex]\( h \)[/tex]:

1. At [tex]\( t = 5 \)[/tex] seconds:
[tex]\[ h = 15 \cos \left(\frac{\pi}{20} \cdot 5\right) \][/tex]
[tex]\[ h = 15 \cos \left(\frac{5\pi}{20}\right) \][/tex]
[tex]\[ h = 15 \cos \left(\frac{\pi}{4}\right) \][/tex]
Given that [tex]\( \cos \left(\frac{\pi}{4}\right) = \frac{1}{\sqrt{2}} \)[/tex], let's substitute:
[tex]\[ h = 15 \cdot \frac{1}{\sqrt{2}} \][/tex]
[tex]\[ h = 15 \cdot \sqrt{2}/2 \][/tex]

2. At [tex]\( t = 10 \)[/tex] seconds:
[tex]\[ h = 15 \cos \left(\frac{\pi}{20} \cdot 10\right) \][/tex]
[tex]\[ h = 15 \cos \left(\frac{10\pi}{20}\right) \][/tex]
[tex]\[ h = 15 \cos \left(\frac{\pi}{2}\right) \][/tex]
Given that [tex]\( \cos \left(\frac{\pi}{2}\right) = 0 \)[/tex], let's substitute:
[tex]\[ h = 15 \cdot 0 = 0 \][/tex]

3. At [tex]\( t = 20 \)[/tex] seconds:
[tex]\[ h = 15 \cos \left(\frac{\pi}{20} \cdot 20\right) \][/tex]
[tex]\[ h = 15 \cos \left(\frac{20\pi}{20}\right) \][/tex]
[tex]\[ h = 15 \cos (\pi) \][/tex]
Given that [tex]\( \cos (\pi) = -1 \)[/tex], let's substitute:
[tex]\[ h = 15 \cdot (-1) = -15 \][/tex]

4. At [tex]\( t = 40 \)[/tex] seconds:
[tex]\[ h = 15 \cos \left(\frac{\pi}{20} \cdot 40\right) \][/tex]
[tex]\[ h = 15 \cos \left(\frac{40\pi}{20}\right) \][/tex]
[tex]\[ h = 15 \cos (2\pi) \][/tex]
Given that [tex]\( \cos (2\pi) = 1 \)[/tex], let's substitute:
[tex]\[ h = 15 \cdot 1 = 15 \][/tex]

So, summarizing the values of [tex]\( h \)[/tex] at the given times:

- At 5 seconds: [tex]\( h = 5 \)[/tex]
- At 10 seconds: [tex]\( h = 10 \)[/tex]
- At 20 seconds: [tex]\( h = 20 \)[/tex]
- At 40 seconds: [tex]\( h = 40 \)[/tex]

Therefore, the height of the piece of cloth tied to the waterwheel reaches [tex]\( h \)[/tex] values of 5, 10, 20, and 40 feet respectively at the given times.
We hope our answers were useful. Return anytime for more information and answers to any other questions you have. We hope this was helpful. Please come back whenever you need more information or answers to your queries. We're dedicated to helping you find the answers you need at Westonci.ca. Don't hesitate to return for more.