Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

Estimate the moment of inertia of a bicycle wheel 67 cm in diameter. The rim and tire have a combined mass of 1.1 kg. The mass of the hub (at the center) can be ignored (why?).

Short Answer

Expert verified

The moment of inertia of the wheel is \(0.12\;{\rm{kg}}\;{{\rm{m}}^2}\).

Step by step solution

01

Identification of the given data

The mass of the wheel is \(m = 1.1\;{\rm{kg}}\).

The diameter of the wheel is \(d = 67\;{\rm{cm}} = 0.67\;{\rm{m}}\).

02

Definition of moment of inertia

Moment of inertia is a quantity that expresses a body’s tendency to resist angular acceleration about the axis of rotation.

It is given as the product of the mass of a rigid body and the square of the distance from the axis of rotation.

\(I = m{r^2}\)

03

Determination of the moment of inertia of the solid sphere

Consider the rim and the tire as a hoop where all of the significant masses are located at the same distance \(\left( {r = \frac{d}{2}} \right)\) from the axis of rotation. Thus, the moment of inertia of the wheel will be given by:

\(\begin{align}I &= m{r^2}\\ &= \left( {1.1\;{\rm{kg}}} \right){\left( {\frac{{0.067}}{2}\;{\rm{m}}} \right)^2}\\ &= \left( {1.1\;{\rm{kg}}} \right){\left( {0.335\;{\rm{m}}} \right)^2}\\ &= 0.12\;{\rm{kg}}\;{{\rm{m}}^2}\end{align}\)

The mass of the hub can be ignored because its distance from the axis of rotation is significantly less (approximately r = 0). So, it has a very small rotational inertia.

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

Question:(II) A ball of radius rrolls on the inside of a track of radius R(see Fig. 8–53). If the ball starts from rest at the vertical edge of the track, what will be its speed when it reaches the lowest point of the track, rolling without slipping?

A hollow cylinder (hoop) is rolling on a horizontal surface at speed v = 3.0 m/s when it reaches a 15° incline. (a) How far up the incline will it go? (b) How long will it be on the incline before it arrives back at the bottom?

To get a flat, uniform cylindrical satellite spinning at the correct rate, engineers fire four tangential rockets, as shown in Fig. 8–50. Suppose that the satellite has a mass of 3600 kg and a radius of 4.0 m and that the rockets each add a mass of 250 kg. What is the steady force required of each rocket if the satellite is to reach 32 rpm in 5.0 min, starting from rest?

FIGURE 8-50

Problem 45

Bicycle gears: (a) How is the angular velocity\({{\bf{\omega }}_{\bf{R}}}\) of the rear wheel of a bicycle related to the angular velocity\({{\bf{\omega }}_{\bf{F}}}\)of the front sprocket and pedals? Let \({{\bf{N}}_{\bf{F}}}\) and \({{\bf{N}}_{\bf{R}}}\) be the number of teeth on the front and rear sprockets, respectively, Fig. 8–58. The teeth are spaced the same on both sprockets and the rear sprocket is firmly attached to the rear wheel. (b) Evaluate the ratio when the front and rear sprockets have 52 and 13 teeth, respectively, and (c) when they have 42 and 28 teeth.

Assume that a 1.00-kg ball is thrown solely by the action of the forearm, which rotates about the elbow joint under the action of the triceps muscle, as shown in Fig. 8–46. The ball is accelerated uniformly from rest to 8.5 m/s in 0.38 s, at which point it is released. Calculate (a) the angular acceleration of the arm and (b) the force required for the triceps muscle. Assume that the forearm has a mass of 3.7 kg, and it rotates like a uniform rod about an axis at its end.

FIGURE 8-46

Problems 35 and 36

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