/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 42 On another planet that you are e... [FREE SOLUTION] | 91Ó°ÊÓ

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On another planet that you are exploring, a large tank is open to the atmosphere and contains ethanol. A horizontal pipe of cross sectional area \(9.0 \times 10^{-4} \mathrm{~m}^{2}\) has one end inserted into the tank just above the bottom of the tank. The other end of the pipe is open to the atmosphere. The viscosity of the ethanol can be neglected. You measure the volume flow rate of the ethanol from the tank as a function of the depth \(h\) of the ethanol in the tank. If you graph the volume flow rate squared as a function of \(h,\) your data lie close to a straight line that has slope \(1.94 \times 10^{-5} \mathrm{~m}^{5} / \mathrm{s}^{2} .\) What is the value of \(g,\) the acceleration of a free-falling object at the surface of the planet?

Short Answer

Expert verified
By doing this calculation, we find that \(g\) is approximately \(10.8 \mathrm{~m/s}^{2}\).

Step by step solution

01

Identifying Given Variables

We are given that the cross-sectional area of the pipe \(A\) is \(9.0 \times 10^{-4} \mathrm{~m}^{2}\). The slope of the graph of \(Q^2\) as a function of \(h\) is also given as \(1.94 \times 10^{-5} \mathrm{~m}^{5} / \mathrm{s}^{2}\). This slope represents the value of \(2Ag\).
02

Solving for g

We know that \(Q = Av\) (speed of liquid flow) and from fluid dynamics, \(v = \sqrt{2gh}\). Substituting into \(Q = Av\), we get \(Q = A\sqrt{2gh}\) or \(Q^2 = 2A^2gh = 2Ag \times h\) (since speed and hence flow rate are dependent on \(A\) and \(g\)). So, the slope of \(Q^2\) vs. \(h\) gives us \(2Ag\). We can solve for \(g\), the acceleration due to gravity, by dividing the given slope by \(2A\).
03

Calculation

Divide the slope given in the problem, \(1.94 \times 10^{-5} \mathrm{~m}^{5} / \mathrm{s}^{2}\), by twice the cross-sectional area of the pipe, \(2 \times (9.0 \times 10^{-4} \mathrm{~m}^{2})\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Volume Flow Rate
Volume flow rate, often symbolized as \(Q\), is a key concept in fluid dynamics. It measures how much fluid passes through a given cross-section of a pipe per unit of time. It's like counting how many cups of water flow from a hose each minute. This can be represented mathematically as:
  • \(Q = A \times v\)
where \(A\) is the cross-sectional area of the pipe, and \(v\) is the velocity of the fluid flowing through it. In simpler terms, it's the velocity of the liquid multiplied by the area through which it flows.
Understanding this concept helps us analyze situations where fluid moves, like water flowing through a pipe or blood circulating in veins. In our exercise, knowing the volume flow rate allows us to explore how the flow changes with different depths \(h\) of liquid in the tank. This relationship was expressed in a graph with \(Q^2\) plotted against \(h\), helping determine other unknown variables such as the acceleration due to gravity on that planet.
Cross-Sectional Area
The cross-sectional area \(A\) plays a crucial role in determining the volume flow rate of a fluid. Imagine slicing a pipe perpendicular to its length and then measuring the space within the boundary of that slice. That's the cross-sectional area.
  • The larger the area, the more fluid can flow through at any given speed.
  • Conversely, a smaller area constricts the flow.
In mathematics, the cross-sectional area is measured in square meters (\(m^2\)), and it directly affects how much fluid can pass through the pipe.In the given problem, the cross-sectional area is \(9.0 \times 10^{-4} \mathrm{~m}^{2}\). This value is essential when calculating the volume flow rate \(Q\) through the pipe as it determines the fluid's velocity. The cross-sectional area is particularly significant in our calculations for finding the acceleration due to gravity \(g\). It's because the slope of the volume flow rate squared graph, \(Q^2\), relates to \(2Ag\) (twice the cross-sectional area multiplied by gravity). So, understanding the area helps in solving related formulas and interpreting fluid movement accurately.
Acceleration due to Gravity
Acceleration due to gravity, denoted as \(g\), reflects the force exerted by a planet on objects at its surface, causing them to fall towards the center of the planet. On Earth, this value is approximately \(9.81 \mathrm{~m/s^2}\), but it can vary on other planets.In the exercise, one goal is to determine \(g\) by analyzing the flow of ethanol from a tank. The relationship between volume flow rate and gravity stems from Bernoulli's principle in fluid dynamics. According to Bernoulli, the velocity \(v\) of a fluid flowing out of an opening can be calculated as:
  • \(v = \sqrt{2gh}\)
Here, \(h\) is the depth of the fluid. This equation links the speed of fluid exiting a tank to the height of the fluid and the local gravitational acceleration.By graphing \(Q^2\) against \(h\), the slope of this graph can tell us about \(2Ag\), from which we can solve for \(g\). Thus, gravity directly influences the speed and therefore the volume of fluid that can escape the tank, integrating it seamlessly into our calculations.

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Most popular questions from this chapter

A firehose must be able to shoot water to the top of a building \(28.0 \mathrm{~m}\) tall when aimed straight up. Water enters this hose at a steady rate of \(0.500 \mathrm{~m}^{3} / \mathrm{s}\) and shoots out of a round nozzle. Neglect air resistance. (a) What is the maximum diameter this nozzle can have? (b) If the only nozzle available has a diameter twice as great, what is the highest point the water can reach?

In intravenous feeding, a needle is inserted in a vein in the patient's arm and a tube leads from the needle to a reservoir of fluid (density \(\left.1050 \mathrm{~kg} / \mathrm{m}^{3}\right)\) located at height \(h\) above the arm. The top of the reservoir is open to the air. If the gauge pressure inside the vein is \(5980 \mathrm{~Pa}\), what is the minimum value of \(h\) that allows fluid to enter the vein? Assume the needle diameter is large enough that you can ignore the viscosity (see Section 12.6 ) of the fluid.

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You are doing experiments from a research ship in the Atlantic Ocean. On a day when the atmospheric pressure at the surface of the water is \(1.03 \times 10^{5} \mathrm{~Pa}\), at what depth below the surface of the water is the absolute pressure (a) twice the pressure at the surface and (b) four times the pressure at the surface?

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