/*! 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 5 \(\cdot\) If a wheel 212 \(\math... [FREE SOLUTION] | 91Ó°ÊÓ

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\(\cdot\) If a wheel 212 \(\mathrm{cm}\) in diameter takes 2.25 s for each revolution, find its (a) period and (b) angular speed in rad/s.

Short Answer

Expert verified
(a) Period is 2.25 s; (b) Angular speed is approximately 2.79 rad/s.

Step by step solution

01

Calculate the Period

The period (\(T\)) of an object is the time it takes to complete one full cycle or revolution. For the given wheel, the period is equal to the time taken for one revolution, which is given as 2.25 seconds. Therefore, \(T = 2.25 \text{ s}\).
02

Find the Angular Speed

Angular speed (\(\omega\)) is defined as the change in angular displacement per unit of time. The formula for angular speed is \(\omega = \frac{2\pi}{T}\), where \(T\) is the period. Substituting \(T = 2.25\) s into the equation, \(\omega = \frac{2\pi}{2.25} \approx 2.79 \text{ rad/s}\).

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Key Concepts

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

Period of Rotation
The period of rotation, represented as \(T\), is a fundamental concept in understanding circular motion. It refers to the time taken by an object to complete one full revolution or cycle around a circle. In the original exercise, the wheel completes one full circle in 2.25 seconds. This value directly represents the period.

Knowing the period of an object in rotational motion allows us to calculate other aspects of its movement, like angular speed or frequency. When you think about the period, imagine how long it takes the hands of a clock to return to the same number once they complete one full circle. It is the time for one complete rotation.

In practical contexts, periods play an essential role in mechanics and engineering, especially when designing gears, motors, or timing devices, as these systems require precise control over rotational cycles.
Circular Motion
Circular motion is observed when an object moves along a circular path. This type of motion is governed by various physical principles and involves several measurements, such as radius, speed, and angular displacement. In the context of the exercise, the wheel motion represents circular motion, which happens because the wheel rotates around its center point.

Key characteristics of circular motion include:
  • Constant Radius: The distance from the circle's center remains unchanged.
  • Continuous Revolution: The path repeats every full revolution, creating a stable trajectory.
Understanding circular motion involves analyzing how force and speed vary as an object travels around the circle. For instance, in a wheel, friction and centripetal force ensure the wheel maintains its circular path. By comprehending how these forces work together, you can predict and control the motion of rotational systems, enhancing designs in mechanics and technology.
Rotational Kinematics
Rotational kinematics deals with the motion of objects that rotate. It is analogous to linear kinematics, which involves objects moving in straight lines, but focuses on parameters such as angular velocity, angular acceleration, and angular displacement. These metrics help describe how an object rotates over time.

In the exercise, you encounter angular speed, a key component of rotational kinematics. Angular speed, denoted as \(\omega\), describes how quickly an object rotates, and is given in radians per second. It captures the rate at which an angle is swept by a radius in a circular path.

Useful equations in rotational kinematics include:
  • \(\omega = \frac{2\pi}{T}\)
  • \(\theta = \omega t\)
where \(\theta\) is the angular displacement, and \(t\) is the time taken.
Rotational kinematics is critical for anything involving spinning objects, from wheels to planets. Mastery of these concepts provides a strong foundation for understanding the mechanics of rotation, crucial in fields ranging from engineering to astrophysics.

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Most popular questions from this chapter

You need to design an industrial turntable that is 60.0 cm in diameter and has a kinetic energy of 0.250 J when turning at 45.0 rpm v (a) What must be the moment of inertia of the turntable about the rotation axis? (b) If your workshop makes this turntable in the shape of a uniform solid disk, what must be its mass?

\(\bullet\) An airplane propeller is rotating at 1900 \(\mathrm{rpm.}\) (a) Compute the propeller's angular velocity in rad/s. (b) How many seconds does it take for the propeller to turn through \(35^{\circ} ?\) (c) If the propeller were turning at \(18 \mathrm{rad} / \mathrm{s},\) at how many rpm would it be turning? (d) What is the period (in seconds) of this propeller?

In redesigning a piece of equipment, you need to replace a solid spherical part of mass \(M\) with a hollow spherical shell of the same size. If both parts must spin at the same rate about an axis through their center, and the new part must have the same kinetic energy as the old one, what must be the mass of the new part in terms of \(M ?\)

A thin uniform bar has two small balls glued to its ends. The bar is 2.00 \(\mathrm{m}\) long and has mass \(4.00 \mathrm{kg},\) while the balls each have mass 0.500 \(\mathrm{kg}\) and can be treated as point masses. Find the moment of inertia of this combination about each of the following axes: (a) an axis perpendicular to the bar through its center; (b) an axis perpendicular to the bar through one of the balls; (c) an axis parallel to the bar through both balls.

A A wall clock on Planet \(X\) has two hands that are aligned at midnight and turn in the same direction at uniform rates, one at 0.0425 \(\mathrm{rad} / \mathrm{s}\) and the other at 0.0163 \(\mathrm{rad} / \mathrm{s}\) . At how many seconds after midnight are these hands (a) first aligned and (b) next aligned?

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