/*! 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 1 A flexible straight wire 75.0 \(... [FREE SOLUTION] | 91Ó°ÊÓ

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A flexible straight wire 75.0 \(\mathrm{cm}\) long is bent into the arc of a circle of radius 2.50 \(\mathrm{m} .\) What angle (in radians and degrees) will this arc subtend at the center of the circle?

Short Answer

Expert verified
The angle is 0.3 radians or approximately 17.19 degrees.

Step by step solution

01

Convert Wire Length to Meters

The wire length is given as 75.0 cm. Since 1 meter equals 100 cm, we convert the wire length to meters by dividing by 100.\(75.0 \text{ cm} = \frac{75.0}{100} \text{ m} = 0.75 \text{ m} \)
02

Use the Arc Length Formula

The arc length \(s\) of a circle is given by the formula \(s = r\theta\), where \(r\) is the radius and \(\theta\) is the angle in radians. Here, \(s = 0.75\text{ m}\) and \(r = 2.50\text{ m}\). Rearrange the formula to find \(\theta\): \(\theta = \frac{s}{r}\).
03

Substitute Values into the Formula

Substitute the known values into the rearranged formula: \(\theta = \frac{0.75}{2.50} = 0.3\text{ radians}\).
04

Convert Radians to Degrees

To convert radians to degrees, multiply by \(\frac{180}{\pi}\). Thus, \(0.3 \text{ radians} \times \frac{180}{\pi} \approx 17.19^{\circ}\).

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Key Concepts

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

Arc Length
The concept of arc length refers to the distance along the curved path of a circle or any curved formation. When we're dealing with circular motion or an arc of a circle, the arc length is a crucial measurement. It can be thought of as the 'unrolled' portion of the circle. To determine the arc length, the formula used is \(s = r\theta\), where \(s\) represents the arc length, \(r\) is the radius of the circle, and \(\theta\) is the angle in radians.

It's important to note that \(\theta\) must be in radians when using this formula. This specification ensures that the arc length directly relates to the circumference calculated as \(2\pi r\). Understanding how to convert between arc length and angles is an essential skill in circle geometry.
  • Always ensure that the angle is in radians when calculating arc length using the formula.
  • An arc is part of a circle's circumference, which is essential for many applications in physics and engineering.
  • Practicing the conversion between degrees and radians will enhance your ability to work with arcs.
Radians to Degrees Conversion
Radians and degrees are both units used for measuring angles. Converting between these two is a fundamental skill in trigonometry and geometry. One radian is the angle created when the arc length equals the radius of the circle. A full circle is equivalent to \(2\pi\) radians or \(360^{\circ}\).

To convert radians to degrees, you can use the conversion factor \(\frac{180}{\pi}\). This factor comes from the equivalence of \(180^{\circ}\) being equal to \(\pi\) radians.
  • Convert radians to degrees by multiplying by \(\frac{180}{\pi}\).
  • Remember, one complete circle is \(2\pi\) radians or \(360^{\circ}\).
  • Consistently practicing conversions will help internalize these relationships.
Radius of a Circle
The radius of a circle is a significant distance from the center to any point along the perimeter of the circle. It's a fundamental element in all circle-related calculations, including those of circumference, area, and arc length. In equations, it is often represented by the letter \(r\).

A circle's radius plays a crucial role in determining its size and the arc length of any arc formed from it. Radius is directly involved in formulas like the circumference \(C = 2\pi r\) and area \(A = \pi r^2\). In the context of arc length, it sets the scale for how large the arc will be.
  • The radius is crucial for calculating both the area and circumference of a circle.
  • Since the radius is a fundamental component of circles, knowing its value is essential.
  • Changing the radius alters the size and properties of the circle proportionally.

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Most popular questions from this chapter

A circular saw blade 0.200 \(\mathrm{m}\) in diameter starts from rest. In 6.00 \(\mathrm{s}\) , it reaches an angular velocity of 140 \(\mathrm{rad} / \mathrm{s}\) with constant angular acceleration. Find the angular acceleration and the angle through which the blade has turned in this time.

A string is wrapped several times around the rim of a small hoop with a radius of 0.0800 \(\mathrm{m}\) and a mass of 0.180 \(\mathrm{kg}\) . If the free end of the string is held in place and the hoop is released from rest (see Figure 9.30), calculate the angular speed of the rotating hoop after it has descended 0.750 \(\mathrm{m} .\)

\(\bullet\) Dental hygiene. Electric toothbrushes can be effective in removing dental plaque. One model consists of a head 1.1 cm in diameter that rotates back and forth through a \(70.0^{\circ}\) angle 7600 times per minute. The rim of the head contains a thin row of bristles. (See Figure 9.25.) (a) What is the average angular speed in each direction of the rotating head, in rad/s? (b) What is the average linear speed in each direction of the bristles against the teeth? (c) Using your own observations, what is the approximate speed of the bristles against your teeth when you brush by hand with an ordinary toothbrush?

\(\cdot\) 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.

\(\bullet\) (a) A cylinder 0.150 \(\mathrm{m}\) in diameter rotates in a lathe at 620 \(\mathrm{rpm} .\) What is the tangential speed of the surface of the cylinder? (b) The proper tangential speed for machining cast iron is about 0.600 \(\mathrm{m} / \mathrm{s} .\) At how many revolutions per minute should a piece of stock 0.0800 \(\mathrm{m}\) in diameter be rotated in a lathe to produce this tangential speed?

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