/*! 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 29 A flywheel with radius \(0.300 \... [FREE SOLUTION] | 91影视

91影视

A flywheel with radius \(0.300 \mathrm{~m}\) starts from rest and accelerates with a constant angular acceleration of \(0.600 \mathrm{rad} / \mathrm{s}^{2} .\) For a point on the rim of the flywheel, what are the magnitudes of the tangential, radial, and resultant accelerations after \(2.00 \mathrm{~s}\) of acceleration?

Short Answer

Expert verified
The magnitudes of the tangential, radial, and resultant accelerations after 2.00 s of acceleration are 0.180 m/s^2, 0.432 m/s^2, and 0.465 m/s^2, respectively.

Step by step solution

01

Determine Tangential Acceleration

The tangential acceleration (tangential component of linear acceleration) of a point on the rim of the flywheel after a certain time can be found using the formula \(a_t = \alpha r\) where \(a_t\) is the tangential acceleration, \(\alpha\) is the angular acceleration, and \(r\) is the radius of the wheel. Plugging in the given values we get \(a_t = 0.600 \, rad/s^2 \times 0.300 \, m = 0.180 \, m/s^2\).
02

Calculate Radial Acceleration

The radial acceleration (centripetal component of linear acceleration) at any instance in a rotating system like this can be calculated using the formula \(a_r = 蠅虏r\). However, the angular speed 蠅 is not given here, so you have to use another formula: \(蠅 = 伪t\) to calculate it first, where \(t\) is the time that the system has been accelerating. Plugging in the given values we get \(蠅 = 0.600 \, rad/s^2 \times 2.00 \, s = 1.20 \, rad/s\). Then we can substitute \( 蠅 \) back into \(a_r = 蠅虏r\): \(a_r = (1.20 \, rad/s)^2 \times 0.300 \, m = 0.432 \, m/s^2 \).
03

Find Resultant Acceleration

The resultant acceleration (as combined effect of both tangential and radial acceleration) can be worked out by the formula \( a = \sqrt{a_t^2 + a_r^2}\). Plugging in our values we get \(a = \sqrt{(0.180 \, m/s^2)^2 + (0.432 \, m/s^2)^2} = 0.465 \, m/s^2 \).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

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

Tangential Acceleration
When an object rotates, such as a point on the rim of a flywheel, it experiences different forms of acceleration. One of these is tangential acceleration, which is the rate at which the linear (or tangential) speed of the object changes. It represents how quickly the velocity of the object is changing along the edge of the circular path.

For an object moving in circular motion with a constant angular acceleration, the tangential acceleration is a linear acceleration tangent to the circle at the object's position. It can easily be calculated using the formula:
\[\begin{equation} a_t = \text{angular acceleration} \times r \end{equation}\]where \(a_t\) is the tangential acceleration, and \(r\) is the radius of the object's circular path. The SI unit for tangential acceleration is meters per second squared \(m/s^2\). An important point to remember is that tangential acceleration only affects the magnitude of velocity, not its direction.

In our flywheel example, the angular acceleration provided is \(0.600 \text{rad/s}^2\), and the flywheel's radius is \(0.300 \text{m}\). Therefore:
\[\begin{equation}a_t = 0.600 \text{rad/s}^2 \times 0.300 \text{m} = 0.180 \text{m/s}^2\end{equation}\]This is how we measure the change in speed for a point on the flywheel's rim over time.
Radial Acceleration
Radial acceleration, on the other hand, refers to the object's acceleration towards the center of its circular path, often called centripetal acceleration. This force is what keeps the object moving in a circle rather than flying off in a straight line as per Newton's first law of motion.

The formula for radial acceleration is given by: \[\begin{equation} a_r = \text{angular velocity}^2 \times r \end{equation}\]where \(a_r\) is the radial acceleration, and the angular velocity \(蠅\) is normally in radians per second \(rad/s\). The radius \(r\) is the same as used in the tangential acceleration formula. However, if the angular velocity is not provided, we can first calculate it using the angular acceleration \(伪\) and the time \(t\) with the equation \(蠅 = 伪t\).

In our example, after calculating \(蠅 = 0.600 \text{rad/s}^2 \times 2.00 \text{s} = 1.20 \text{rad/s}\), we use it to find the radial acceleration:\[\begin{equation}a_r = (1.20 \text{rad/s})^2 \times 0.300 \text{m} = 0.432 \text{m/s}^2\end{equation}\]This acceleration is directed towards the center of the flywheel and is responsible for changing the direction of the point's velocity vector.
Resultant Acceleration
When discussing circular motion, it's important to understand that the resultant acceleration is the vector sum of tangential and radial accelerations. This combined acceleration illustrates the overall effect of both changing speed and changing direction on a point moving in a circle.

Given that the tangential and radial accelerations are at right angles to each other (tangent and radius of a circle always meet at a right angle), the resultant acceleration can be calculated using the Pythagorean theorem:\[\begin{equation} a = \text{resultant acceleration} = \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text: \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text: \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text: \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text: \text{ }\text: \text{ }\text{ }\text: \text{ }\text{ }\text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: 魔\text: 魔\text: K\text: 脨\text: Q\text: 脨\text: 脨\text: Z\text: K\text: P\text: M\text: 脨\text: P\text: 脨\text: 1\text: 4\text: 0\text: 0\text: 7\text: 0\text: 4\text: 2\text: 1\text: 0\text: 5\text: 1\text: 2\text: X\text: Y\text: 膭\text: T\text: 臉\text: 膯\text: 呕\text: 膭\text: 殴\text: 艂\text: 艧\text: 臒\text: 5\text: 3\text: 6\text: 4\text: 8\text: 4\text: 3\text: 2\text: 5\text: 4\text: 4\text: 8\text: 3\text: 7\text: 4\text: 8\text: 2\text: 4\text: 1\text: 3\text: 1\text: 6: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: 魔\end{equation}\]Once the tangential acceleration \(a_t\) and radial acceleration \(a_r\) are known, use their values to find the resultant acceleration:\[\begin{equation}a = \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text: \text{ }\text{ }\text: \text{ }\text{ }\text: \text{ }\text{ }\text: \text{ }\text{ }\text: \text{ }\text{ }\text: \text{ }\text{ }\text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: \text: 魔\end{equation}\]In the flywheel example, we calculate it using the previous findings:\[\begin{equation} a = \text{ }\text{ }\text: \text: \text: 魔\end{equation}\]This \(0.465 \text{m/s}^2\) is the overall linear acceleration experienced by a point on the rim of the flywheel after 2 seconds.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A child is pushing a merry-go-round. The angle through which the merry-go- round has turned varies with time according to \(\theta(t)=\gamma t+\beta t^{3}, \quad\) where \(\quad \gamma=0.400 \mathrm{rad} / \mathrm{s} \quad\) and \(\quad \beta=0.0120 \mathrm{rad} / \mathrm{s}^{3}\) (a) Calculate the angular velocity of the merry-go-round as a function of time. (b) What is the initial value of the angular velocity? (c) Calculate the instantaneous value of the angular velocity \(\omega_{z}\) at \(t=5.00 \mathrm{~s}\) and the average angular velocity \(\omega_{\mathrm{av}-z}\) for the time interval \(t=0\) to \(t=5.00 \mathrm{~s}\) Show that \(\omega_{\mathrm{av}-z}\) is \(n o t\) equal to the average of the instantaneous angular velocities at \(t=0\) and \(t=5.00 \mathrm{~s},\) and explain.

A uniform sphere with mass \(M\) and radius \(R\) is rotating with angular speed \(\omega_{1}\) about a frictionless axle along a diameter of the sphere. The sphere has rotational kinetic energy \(K_{1}\). A thin-walled hollow sphere has the same mass and radius as the uniform sphere. It is also rotating about a fixed axis along its diameter. In terms of \(\omega_{1},\) what angular speed must the hollow sphere have if its kinetic energy is also \(K_{1},\) the same as for the uniform sphere?

An airplane propeller is \(2.08 \mathrm{~m}\) in length (from tip to tip) with mass \(117 \mathrm{~kg}\) and is rotating at 2400 rpm (rev/min) about an axis through its center. You can model the propeller as a slender rod. (a) What is its rotational kinetic energy? (b) Suppose that, due to weight constraints, you had to reduce the propeller's mass to \(75.0 \%\) of its original mass, but you still needed to keep the same size and kinetic energy. What would its angular speed have to be, in rpm?

\(\begin{array}{llll}\mathrm{In} & \mathrm{a} & \text { charming } & 19 \text { th-century }\end{array}\) hotel, an old-style elevator is connected to a counterweight by a cable that passes over a rotating disk \(2.50 \mathrm{~m}\) in diameter (Fig. E9.18). The elevator is raised and lowered by turning the disk, and the cable does not slip on the rim of the disk but turns with it. (a) At how many rpm must the disk turn to raise the elevator at \(25.0 \mathrm{~cm} / \mathrm{s} ?\) (b) To start the elevator moving, it must be accelerated at \(\frac{1}{8} g .\) What must be the angular acceleration of the disk, in rad/s \(^{2} ?\) (c) Through what angle (in radians and degrees) has the disk turned when it has raised the elevator \(3.25 \mathrm{~m}\) between floors?

On a compact disc (CD), music is coded in a pattern of tiny pits arranged in a track that spirals outward toward the rim of the disc. As the disc spins inside a CD player, the track is scanned at a constant linear speed of \(v=1.25 \mathrm{~m} / \mathrm{s} .\) Because the radius of the track varies as it spirals outward, the angular speed of the disc must change as the \(\mathrm{CD}\) is played. (See Exercise \(9.20 .\) ) Let's see what angular acceleration is required to keep \(v\) constant. The equation of a spiral is \(r(\theta)=r_{0}+\beta \theta,\) where \(r_{0}\) is the radius of the spiral at \(\theta=0\) and \(\beta\) is a constant. On a \(\mathrm{CD}, r_{0}\) is the inner radius of the spiral track. If we take the rotation direction of the CD to be positive, \(\beta\) must be positive so that \(r\) increases as the disc turns and \(\theta\) increases. (a) When the disc rotates through a small angle \(d \theta,\) the distance scanned along the track is \(d s=r d \theta .\) Using the above expression for \(r(\theta),\) integrate \(d s\) to find the total distance \(s\) scanned along the track as a function of the total angle \(\theta\) through which the disc has rotated. (b) since the track is scanned at a constant linear speed \(v,\) the distance \(s\) found in part (a) is equal to vi. Use this to find \(\theta\) as a function of time. There will be two solutions for \(\theta ;\) choose the positive one, and explain why this is the solution to choose. (c) Use your expression for \(\theta(t)\) to find the angular velocity \(\omega_{z}\) and the angular acceleration \(\alpha_{z}\) as functions of time. Is \(\alpha_{z}\) constant? (d) On a CD, the inner radius of the track is \(25.0 \mathrm{~mm}\), the track radius increases by \(1.55 \mu \mathrm{m}\) per revolution, and the playing time is \(74.0 \mathrm{~min} .\) Find \(r_{0}, \beta,\) and the total number of revolutions made during the playing time. (e) Using your results from parts (c) and (d), make graphs of \(\omega_{z}\) (in rad/s) versus \(t\) and \(\alpha_{z}\) (in rad/s \(^{2}\) ) versus \(t\) between \(t=0\) and \(t=74.0 \mathrm{~min}\)

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.