/*! 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 15 To measure the acceleration due ... [FREE SOLUTION] | 91Ó°ÊÓ

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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 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 on the planet is approximately 7.64 m/s².

Step by step solution

01

Calculate the Speed of the Pulse

First, determine the speed of the transverse pulse traveling through the wire. The velocity \( v \) of a pulse in a stretched string can be calculated using the formula \( v = \frac{L}{t} \), where \( L \) is the length of the wire and \( t \) is the travel time. Given \( L = 0.95 \text{ m} \) and \( t = 0.016 \text{ s} \), calculate \( v = \frac{0.95}{0.016} = 59.375 \text{ m/s} \).
02

Apply Pulse Velocity Formula

The speed of the pulse \( v \) on a string is also given by the formula \( v = \sqrt{\frac{T}{\mu}} \), where \( T \) is the tension in the string and \( \mu \) is the linear density. Plug in the values: \( \mu = 1.2 \times 10^{-4} \text{ kg/m} \) and \( v = 59.375 \text{ m/s} \).
03

Solve for the Tension in the Wire

Rearrange the pulse velocity formula to solve for \( T \): \( T = \mu v^2 \). Substitute \( \mu = 1.2 \times 10^{-4} \text{ kg/m} \) and \( v = 59.375 \text{ m/s} \) to get \( T = 1.2 \times 10^{-4} \times (59.375)^2 = 0.420 \text{ N} \).
04

Relate Tension to Gravitational Force

The tension in the wire is equal to the gravitational force acting on the ball since the mass of the wire is negligible. Use the formula \( T = mg \) to solve for \( g \), the acceleration due to gravity: \( g = \frac{T}{m} \), where \( m = 0.055 \text{ kg} \).
05

Calculate Acceleration Due to Gravity

Substitute \( T = 0.420 \text{ N} \) and \( m = 0.055 \text{ kg} \) into the equation for \( g \): \( g = \frac{0.420}{0.055} = 7.64 \text{ m/s}^2 \).

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Key Concepts

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

Transverse Pulse
In the context of wave physics, a transverse pulse refers to a disturbance that moves along a medium. In this case, the medium is the wire. As the pulse travels, the particles in the wire will move perpendicular to the direction of the wave. This is akin to flicking a rope and seeing the wave propagate from one end to the other.
Understanding the speed at which a transverse pulse moves along the wire is crucial to solving for acceleration due to gravity. The speed of this pulse is determined by both the material properties of the wire, such as its linear density, and the tension applied to it. This plays into the calculation of other variables like the acceleration due to gravity.
For the astronaut's experiment, knowing the travel time and the length of the wire enables the calculation of the pulse speed by using the formula:
  • \( v = \frac{L}{t} \)
Where \( L \) represents the length of the wire and \( t \) the time taken by the pulse to travel this distance.
Tension in String
The tension in the string or wire is a force that is crucial for maintaining the wave motion. In this scenario, it is the force exerted by the wire against the gravitational pull acting on the hanging ball. When a transverse pulse travels along the wire, the tension affects how fast the wave travels.
To find the tension, first, understand that it can be calculated using the pulse velocity and the linear density of the wire through the formula:
  • \(v = \sqrt{\frac{T}{\mu}}\)
Rearranging this equation helps in solving the tension \(T\) as:
  • \(T = \mu v^2\)
Once the speed of the pulse \(v\) is known, substitute it back into the equation along with the wire’s linear density \(\mu\) to compute the wire's tension. This calculation is necessary to further relate this tension to the gravitational force and the acceleration due to gravity.
Linear Density of Wire
Linear density is an important factor in the behavior of waves along a medium like a wire. It is defined as the mass per unit length of the wire and denoted by \(\mu\). In mathematical terms:
\(\mu = \frac{m}{L}\)
where \(m\) is the mass of the wire, and \(L\) is its length. However, since the exercise indicates the mass of the wire is negligible, direct calculation from this is not significant for the given problem.
What’s vital is to use the linear density value to compute the tension in the string once the pulse speed is known. Since the linear density directly affects the velocity of transverse waves, having an accurate measure of \(\mu\) is essential to ensure precision in these calculations.
For the astronaut’s experiment, the linear density helps in bridging the pulse speed with the force calculations. This means understanding how denser or less dense wires might contribute differently to the behavior of pulses, concerning wave speed and further, acceleration due to gravity.

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Most popular questions from this chapter

A middle-aged man typically has poorer hearing than a middle-aged woman. In one case a woman can just begin to hear a musical tone, while a man can just begin to hear the tone only when its intensity level is increased by \(7.8 \mathrm{dB}\) relative to the just-audible intensity level for the woman. What is the ratio of the sound intensity just detected by the man to the sound intensity just detected by the woman?

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