A wheel with \(c=\frac{4}{9}\), a mass of \(40.0 \mathrm{~kg}\), and a rim radius of \(30.0 \mathrm{~cm}\) is mounted vertically on a horizontal axis. A 2.00 -kg mass is suspended from the wheel by a rope wound around the rim. Find the angular acceleration of the wheel when the mass is released.

Short Answer

Expert verified
#tag_title#Answer#tag_content# When the mass is released, the angular acceleration of the wheel is given by the formula: \(α = \frac{\tau}{I} = \frac{rF}{\frac{1}{2}MR^2}\). First, we calculate the force exerted by the suspended mass: \(F = mg = (2.00 \mathrm{~kg})(9.81 \mathrm{~m/s^2}) = 19.62 \mathrm{~N}\). Next, we calculate the moment of inertia of the wheel: \(I = \frac{1}{2}(40.0 \mathrm{~kg})(0.3 \mathrm{~m})^2 = 1.8 \mathrm{~kg \cdot m^2}\). Now, we substitute the values of torque and moment of inertia into the formula for angular acceleration: \(α = \frac{(0.3 \mathrm{~m})(19.62 \mathrm{~N})}{1.8 \mathrm{~kg \cdot m^2}} = 3.27 \mathrm{~rad/s^2}\). Therefore, the angular acceleration of the wheel when the mass is released is \(3.27 \mathrm{~rad/s^2}\).

Step by step solution

01

Identify the forces acting on the system

There are two forces acting on the system: the gravitational force acting on the suspended mass and the tension in the rope. The gravitational force acting on the mass causes it to accelerate downward and exerts a torque on the wheel, causing it to rotate. The tension in the rope opposes the gravitational force and also exerts a torque on the wheel.
02

Determine the moment of inertia of the wheel

To calculate the moment of inertia for the wheel, we can use the formula for a solid cylinder, \(I = \frac{1}{2}MR^2\) where \(M\) is the mass of the wheel, and \(R\) is the rim radius. The moment of inertia of the wheel is: \(I = \frac{1}{2}(40.0 \mathrm{~kg})(0.3 \mathrm{~m})^2\)
03

Calculate the torque acting on the wheel due to the suspended mass

The torque acting on the wheel due to the suspended mass can be estimated using the formula: \(\tau = rF\), where \(r\) is the radius of the rim, and \(F\) is the force exerted by the suspended mass (the gravitational force acting on the mass). The force exerted by the suspended mass is: \(F = mg\), where \(m = 2.00 \mathrm{~kg}\) (the mass of the suspended weight), and \(g = 9.81 \mathrm{~m/s^2}\) (acceleration due to gravity).
04

Use Newton's second law for rotation to find the angular acceleration

Newton's second law for rotation states that the angular acceleration (α) is equal to the torque (τ) divided by the moment of inertia (I): \(α = \frac{\tau}{I}\). Substituting the expressions for torque and moment of inertia, we find the angular acceleration when the mass is released.

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 Vaia!

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

Determine the moment of inertia for three children weighing \(60.0 \mathrm{lb}, 45.0 \mathrm{lb}\) and \(80.0 \mathrm{lb}\) sitting at different points on the edge of a rotating merry-go-round, which has a radius of \(12.0 \mathrm{ft}\).

A thin uniform rod (length \(=1.00 \mathrm{~m},\) mass \(=2.00 \mathrm{~kg})\) is pivoted about a horizontal frictionless pin through one of its ends. The moment of inertia of the rod through this axis is \(\frac{1}{3} m L^{2} .\) The rod is released when it is \(60.0^{\circ}\) below the horizontal. What is the angular acceleration of the rod at the instant it is released?

A light rope passes over a light, frictionless pulley. One end is fastened to a bunch of bananas of mass \(M,\) and \(a\) monkey of the same mass clings to the other end. The monkey climbs the rope in an attempt to reach the bananas. The radius of the pulley is \(R\). a) Treating the monkey, bananas, rope, and pulley as a system, evaluate the net torque about the pulley axis. b) Using the result of part (a) determine the total angular momentum about the pulley axis as a function of time

The flywheel of an old steam engine is a solid homogeneous metal disk of mass \(M=120 . \mathrm{kg}\) and radius \(R=80.0 \mathrm{~cm} .\) The engine rotates the wheel at \(500 .\) rpm. In an emergency, to bring the engine to a stop, the flywheel is disengaged from the engine and a brake pad is applied at the edge to provide a radially inward force \(F=100 .\) N. If the coefficient of kinetic friction between the pad and the flywheel is \(\mu_{\mathrm{k}}=0.200,\) how many revolutions does the flywheel make before coming to rest? How long does it take for the flywheel to come to rest? Calculate the work done by the torque during this time.

A solid sphere of radius \(R\) and mass \(M\) is placed at a height \(h_{0}\) on an inclined plane of slope \(\theta\). When released, it rolls without slipping to the bottom of the incline. Next, a cylinder of same mass and radius is released on the same incline. From what height \(h\) should it be released in order to have the same speed as the sphere at the bottom?

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.

Sign-up for free