/*! 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 17 Consult Interactive Solution \(\... [FREE SOLUTION] | 91Ó°ÊÓ

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Consult Interactive Solution \(\underline{16.17}\) at in order to review a model for solving this problem. To measure the acceleration due to gravity on a distant planet, an astronaut hangs a \(0.055-\mathrm{kg}\) ball from the end of a wire. The wire has a length of \(0.95 \mathrm{~m}\) and a linear density of \(1.2 \times 10^{-4} \mathrm{~kg} / \mathrm{m}\). Using electronic equipment, the astronaut measures the time for a transverse pulse to travel the length of the wire and obtains a value of \(0.016 \mathrm{~s}\). The mass of the wire is negligible compared to the mass of the ball. Determine the acceleration due to gravity.

Short Answer

Expert verified
The acceleration due to gravity is approximately \(7.65 \text{ m/s}^2\).

Step by step solution

01

Calculate the Mass of the Wire

First, calculate the mass of the wire using its linear density and length. The formula for mass is: \[ m_{wire} = ext{linear density} imes ext{length} \] Given, the linear density is \(1.2 \times 10^{-4} \text{ kg/m}\) and the length \(0.95 \text{ m}\), thus: \[ m_{wire} = 1.2 \times 10^{-4} \text{ kg/m} \times 0.95 \text{ m} \approx 1.14 \times 10^{-4} \text{ kg} \]
02

Determine the Speed of the Pulse

Next, determine the speed of the transverse pulse in the wire using the formula for wave speed:\[ v = \frac{L}{t} \] where \(L = 0.95 \text{ m}\) is the length of the wire and \(t = 0.016 \text{ s}\) is the time taken for the pulse to travel. Thus: \[ v = \frac{0.95 \text{ m}}{0.016 \text{ s}} = 59.375 \text{ m/s} \]
03

Relate Wave Speed to Tension in the Wire

Using the wave speed, relate it to the tension in the wire, where wave speed \(v\) is given by:\[ v = \sqrt{\frac{T}{\mu}} \]\(T\) is the tension (equal to the weight of the ball since the mass of the wire is negligible), and \(\mu\) is the linear density of the wire: \[ 59.375 = \sqrt{\frac{T}{1.2 \times 10^{-4}}} \]
04

Solve for Tension in the Wire

The weight of the ball provides the tension \(T\) in the wire. Solve for \(T\) by squaring the wave speed equation and solving for \(T\):\[ (59.375)^2 = \frac{T}{1.2 \times 10^{-4}} \] \[ T = (59.375)^2 \times 1.2 \times 10^{-4} \approx 0.421 \text{ N} \]
05

Calculate Acceleration due to Gravity

Finally, use the tension \(T\) to find the acceleration due to gravity \(g\), since the tension \(T\) is equal to the weight of the ball:\[ T = m_{ball} \cdot g \] \[ 0.421 = 0.055 \cdot g \] Solve for \(g\):\[ g = \frac{0.421}{0.055} \approx 7.65 \text{ m/s}^2 \]

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Key Concepts

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

Acceleration due to gravity
Measuring acceleration due to gravity helps us understand how strong gravity is in a particular location, like a planet. This force causes objects to fall towards the planet's surface. To determine this force on a distant planet, an astronaut can perform a simple experiment, as shown in the exercise described.
In this experiment, acceleration due to gravity, denoted by the symbol \( g \), is calculated from the tension in a wire. The tension is produced by the weight of a ball.
To recap, the formula used is:
  • \( T = m_{ball} \cdot g \)
Where \( T \) is the tension in the wire, and \( m_{ball} \) is the mass of the ball. By rearranging this formula, you can find \( g \), which tells how strongly gravity pulls the ball downward.
Transverse wave
In the context of this experiment, a transverse wave is a type of wave where the motion of the medium (the wire, in this case) is perpendicular to the direction of the wave's travel.
When the astronaut creates a pulse, it travels across the wire as a transverse wave. It's the wave's speed that helps find the tension in the wire, which in turn is used to calculate gravity.
Transverse waves are common in strings and wires, making them perfect for such experiments. The time it takes for the pulse to move along the wire helps determine how fast these waves are traveling.
Tension in wire
Tension in the wire is a critical component in this experiment because it affects wave speed and is tied directly to the force of gravity acting on the ball.
In simple terms, tension is the force exerted along the wire as a result of the ball's weight. Mathematically, it's expressed using the formula:
  • \( T = m_{ball} \cdot g \)
The tension causes the wire to be tight, which influences how quickly waves can travel through it.
Higher tension means faster waves.
Wave speed calculation
Calculating wave speed is essential to this experiment. The speed of a transverse wave can be determined using the relationship between wave speed, tension in the wire, and linear density.
The formula for the speed \( v \) of a wave is:
  • \( v = \sqrt{\frac{T}{\mu}} \)
Where \( T \) is the tension in the wire and \( \mu \) is the linear density.
For this experiment, the speed can also be simply found with:
  • \( v = \frac{L}{t} \)
Where \( L \) is the length of the wire and \( t \) is the time taken by the wave to traverse its length.
Determining wave speed accurately is a vital step as it forms the link between the physical property measurements and theoretical calculations.
Mass and density
In this context, mass is essential for both calculating tension and interpreting wave speed results. Density, on the other hand, pertains specifically to the wire.
Linear density, denoted \( \mu \), for the wire is used to relate tension and wave speed. The relationship is important because the mass per unit length influences how waves travel through the wire.
To find the mass of the wire, if needed, we multiply its linear density by its length using:
  • \( m_{wire} = \text{linear density} \times \text{length} \)
This shows how these small but critical aspects play a big role in understanding physical properties related to this exercise.

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Most popular questions from this chapter

Concept Questions Multiple-Concept 11 provides a model for solving this type of problem. A wireless transmitting microphone is mounted on a small platform, which can roll down an incline, away from a speaker that is mounted at the top of the incline. The speaker broadcasts a fixed-frequency tone. (a) The platform is positioned in front of the speaker and released from rest. Describe how the velocity of the platform changes and why. (b) How is the changing velocity related to the acceleration of the platform? (c) Describe how the frequency detected by the microphone changes. Explain why the frequency changes as you have described. (d) Which equation given in the chapter applies to this situation? Justify your answer. Problem The speaker broadcasts a tone that has a frequency of \(1.000 \times 10^{4} \mathrm{~Hz}\), and the speed of sound is \(343 \mathrm{~m} / \mathrm{s}\). At a time of \(1.5 \mathrm{~s}\) following the release of the platform, the microphone detects a frequency of \(9939 \mathrm{~Hz}\). At a time of \(3.5 \mathrm{~s}\) following the release of the platform, the microphone detects a frequency of \(9857 \mathrm{~Hz}\). What is the acceleration (assumed constant) of the platform?

Two submarines are underwater and approaching each other head-on. Sub A has a speed of \(12 \mathrm{~m} / \mathrm{s}\) and sub \(\mathrm{B}\) has a speed of \(8 \mathrm{~m} / \mathrm{s}\). Sub A sends out a 1550 -Hz sonar wave that travels at a speed of \(1522 \mathrm{~m} / \mathrm{s}\). (a) What is the frequency detected by sub \(\mathrm{B}\) ? (b) Part of the sonar wave is reflected from \(\mathrm{B}\) and returns to \(\mathrm{A}\). What frequency does A detect for this reflected wave?

Multiple-Concept Example 4 presents one method for modeling this type of problem. Civil engineers use a transit theodolite when surveying. A modern version of this device determines distance by measuring the time required for an ultrasonic pulse to reach a target, reflect from it, and return. Effectively, such a theodolite is calibrated properly when it is programmed with the speed of sound appropriate for the ambient air temperature. (a) Suppose the round-trip time for the pulse is \(0.580 \mathrm{~s}\) on a day when the air temperature is \(293 \mathrm{~K},\) the temperature for which the instrument is calibrated. How far is the target from the theodolite? (b) Assume that air behaves as an ideal gas. If the air temperature were \(298 \mathrm{~K}\), rather than the calibration temperature of \(293 \mathrm{~K}\), what percentage error would there be in the distance measured by the theodolite?

Deep ultrasonic heating is used to promote healing of torn tendons. It is produced by applying ultrasonic sound over the affected area of the body. The sound transducer (generator) is circular with a radius of \(1.8 \mathrm{~cm}\), and it produces a sound intensity of \(5.9 \times 10^{3} \mathrm{~W} / \mathrm{m}^{2}\). How much time is required for the transducer to emit \(4800 \mathrm{~J}\) of sound energy?

A transverse wave is traveling on a string. The displacement \(y\) of a particle from its equilibrium position is given by \(y=(0.021 \mathrm{~m}) \sin (25 t-2.0 x) .\) Note that the phase angle \(25 t-2.0 x\) is in radians, \(t\) is in seconds, and \(x\) is in meters. The linear density of the string is \(1.6 \times 10^{-2} \mathrm{~kg} / \mathrm{m} .\) What is the tension in the string?

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