/*! 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 30 A gyroscope flywheel of radius \... [FREE SOLUTION] | 91Ó°ÊÓ

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A gyroscope flywheel of radius \(2.83 \mathrm{~cm}\) is accelerated from rest at \(14.2 \mathrm{rad} / \mathrm{s}^{2}\) until its angular speed is \(2760 \mathrm{rev} / \mathrm{min} .\) (a) What is the tangential acceleration of a point on the rim of the flywheel during this spin-up process? (b) What is the radial acceleration of this point when the flywheel is spinning at full speed? (c) Through what distance does a point on the rim move during the spin-up?

Short Answer

Expert verified
(a) 0.402 m/s², (b) 2360.61 m/s², (c) 83.33 m.

Step by step solution

01

Convert Units

First, we need to convert the angular speed from revolutions per minute (rpm) to radians per second (rad/s).Given:- Final angular speed = \(2760 \text{ rev/min}\)Conversion factor:- \(1 \text{ rev} = 2\pi \text{ rad}\)- \(1 \text{ min} = 60 \text{ s}\)So, the final angular speed \(\omega_f\) in rad/s is:\[\omega_f = 2760 \times \frac{2\pi}{60} = 289 \text{ rad/s}\]
02

Tangential Acceleration

The tangential acceleration \(a_t\) can be found using the relation:\[ a_t = r\alpha \]where:- \(r = 2.83 \text{ cm} = 0.0283 \text{ m}\)- \(\alpha = 14.2 \text{ rad/s}^2\) (angular acceleration)Substituting in the given values:\[ a_t = 0.0283 \cdot 14.2 = 0.40186 \text{ m/s}^2\]
03

Radial Acceleration

The radial (centripetal) acceleration \(a_r\) when the flywheel is spinning at full speed can be calculated with:\[ a_r = r\omega^2 \]where \(\omega = 289 \text{ rad/s}\).Substituting in the values:\[ a_r = 0.0283 \times (289)^2 = 2360.61 \text{ m/s}^2\]
04

Distance Traveled

To find the distance traveled by a point on the rim, we first find the angular displacement \(\theta\) using the equation:\[ \omega_f^2 = \omega_0^2 + 2\alpha\theta \]Where:- \(\omega_0 = 0\) (initial angular speed)Solving for \(\theta\):\[ 289^2 = 0 + 2 \times 14.2 \times \theta \]\[ \theta = \frac{289^2}{2 \times 14.2} = 2945.14 \text{ rad}\]The linear distance \(s\) is:\[ s = r\theta = 0.0283 \times 2945.14 = 83.3345 \text{ m}\]

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Key Concepts

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

Tangential Acceleration
When we talk about tangential acceleration, we're referring to the linear acceleration experienced by a point on a rotating object, like a gyroscope wheel, along the direction of rotation. Tangential acceleration is a key concept in understanding how quickly an object speeds up its rotation. The formula for calculating tangential acceleration is
  • \(a_t = r \cdot \alpha\)
Here, \(a_t\) is the tangential acceleration, \(r\) is the radius, and \(\alpha\) is the angular acceleration.
In this exercise, the gyroscope flywheel has a radius \(r\) of 2.83 cm (or 0.0283 m in meters), and it's given an angular acceleration of 14.2 rad/s². Thus, each moment it spins faster, every point on the edge of the flywheel becomes quicker too.
Calculating using these values:
  • \(a_t = 0.0283 \times 14.2 = 0.40186 \; \text{m/s}^2\)
This tells us that every second, the point on the rim speeds up by 0.40186 meters per second squared, which might seem modest, but it's crucial for the efficient functioning of devices like gyroscopes.
Radial Acceleration
Radial acceleration, also known as centripetal acceleration, keeps the points on the gyroscope's rim moving in a curved path rather than shooting off in a straight line.
This acceleration always points towards the center of the object's rotation.
The formula to calculate it is:
  • \(a_r = r \cdot \omega^2\)
where \(a_r\) is the radial acceleration, \(r\) is the radius, and \(\omega\) is the angular velocity.
In our case, at the full angular velocity of 289 rad/s (after converting from the original 2760 rpm), and with the radius as 0.0283 m, the radial acceleration is:
  • \(a_r = 0.0283 \times (289)^2 = 2360.61 \; \text{m/s}^2\)
This large value indicates the immense force needed to keep the rim of the spinning gyroscope on its circular path. It's essential for preventing objects from flying outward due to inertia during high-speed rotation.
Angular Displacement
Angular displacement describes the total angle through which a point on the gyroscope rim has traveled over the course of its spinning up from rest. It's a measure of how much rotation has happened.
Angular displacement is crucial in determining the distance a point on the rim has traveled. To find it, you'll typically use this formula:
  • \(\omega_f^2 = \omega_0^2 + 2\alpha\theta\)
where \(\omega_f\) is the final angular speed, \(\omega_0\) is the initial angular speed (which is zero if starting from rest), \(\alpha\) is the angular acceleration, and \(\theta\) is the angular displacement.
From the exercise:
  • With an initial angular speed of 0 and a final speed of 289 rad/s, the angular displacement is:
  • \(\theta = \frac{289^2}{2 \times 14.2} = 2945.14 \; \text{rad}\)
To find the linear distance traveled by the rim's point, the formula used is:
  • \(s = r\theta\)
where \(s\) is the distance.
Plugging in the numbers:
  • \(s = 0.0283 \times 2945.14 = 83.3345 \; \text{m}\)
This means, during its speed increase, a point on the rim travels approximately 83.33 meters, illustrating a considerable motion for such a compact device.

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Most popular questions from this chapter

A car starts from rest and moves around a circular track of radius \(30.0 \mathrm{~m}\). Its speed increases at the constant rate of \(0.500\) \(\mathrm{m} / \mathrm{s}^{2} .\) (a) What is the magnitude of its net linear acceleration \(15.0 \mathrm{~s}\) later? (b) What angle does this net acceleration vector make with the car's velocity at this time?

At \(t=0\), a flywheel has an angular velocity of \(4.7 \mathrm{rad} / \mathrm{s}, \mathrm{a}\) constant angular acceleration of \(-0.25 \mathrm{rad} / \mathrm{s}^{2}\), and a reference line at \(\theta_{0}=0 .\) (a) Through what maximum angle \(\theta_{\max }\) will the reference line turn in the positive direction? What are the (b) first and (c) second times the reference line will be at \(\theta=\frac{1}{2} \theta_{\max } ?\) At what (d) negative time and (e) positive time will the reference line be at \(\theta=10.5\) rad? (f) Graph \(\theta\) versus \(t\), and indicate the answers to (a) through (e) on the graph.

A golf ball is launched at an angle of \(20^{\circ}\) to the horizontal, with a speed of \(60 \mathrm{~m} / \mathrm{s}\) and a rotation rate of \(90 \mathrm{rad} / \mathrm{s}\). Neglecting air drag, determine the number of revolutions the ball makes by the time it reaches maximum height.

A flywheel turns through 40 rev as it slows from an angular speed of \(1.5 \mathrm{rad} / \mathrm{s}\) to a stop. (a) Assuming a constant angular acceleration, find the time for it to come to rest. (b) What is its angular acceleration? (c) How much time is required for it to complete the first 20 of the 40 revolutions?

A flywheel with a diameter of \(1.20 \mathrm{~m}\) is rotating at an angular speed of 200 rev/min. (a) What is the angular speed of the flywheel in radians per second? (b) What is the linear speed of a point on the rim of the flywheel? (c) What constant angular acceleration (in revolutions per minute- squared) will increase the wheel's angular speed to 1000 rev/min in \(60.0 \mathrm{~s}\) ? (d) How many revolutions does the wheel make during that \(60.0 \mathrm{~s}\) ?

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