/*! 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 67 A fan is rotating at a constant ... [FREE SOLUTION] | 91Ó°ÊÓ

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A fan is rotating at a constant 360.0 rev/min. What is the magnitude of the acceleration of a point on one of its blades \(10.0 \mathrm{cm}\) from the axis of rotation?

Short Answer

Expert verified
The magnitude of the acceleration of a point on one of the fan's blades \(10.0 \, \mathrm{cm}\) from the axis of rotation is approximately \(141.96 \, \mathrm{m/s^2}\).

Step by step solution

01

Convert rotational speed to radians per second

Given the rotational speed of the fan is \(360.0\) rev/min, we will convert it to radians per second. Since there are \(2\pi\) radians in one revolution and 60 seconds in a minute, the conversion factor is: \[\omega \,(\mathrm{rad/s}) = \frac{2\pi \, \mathrm{rad}}{1 \, \mathrm{rev}} \times \frac{1 \, \mathrm{minute}}{60 \, \mathrm{seconds}}\] Now, multiply the given rotational speed by the conversion factor: \[\omega = 360.0 \, \mathrm{rev/min} \times \frac{2\pi \, \mathrm{rad}}{1 \, \mathrm{rev}} \times \frac{1 \, \mathrm{minute}}{60 \, \mathrm{seconds}}\]
02

Calculate angular velocity

Perform the calculation to find the angular velocity: \[\omega = 360.0 \times \frac{2\pi}{1} \times \frac{1}{60} \Rightarrow \omega = 37.68 \, \mathrm{rad/s}\]
03

Convert distance from axis of rotation to meters

The given distance from the axis of rotation is \(10.0 \, \mathrm{cm}\). To use this value in our calculation, we need to convert it to meters: \[r = 10.0 \, \mathrm{cm} \times \frac{1 \, \mathrm{meter}}{100 \, \mathrm{cm}} = 0.1 \, \mathrm{meter}\]
04

Calculate centripetal acceleration

Now, we can use the formula for centripetal acceleration: \(a_c = r\omega^2\) Substitute the values of \(r\) and \(\omega\) into the equation: \(a_c = (0.1 \, \mathrm{meter})(37.68 \, \mathrm{rad/s})^2\)
05

Compute the magnitude of the acceleration

Perform the calculation to find the magnitude of the acceleration: \(a_c = (0.1)(37.68)^2 \Rightarrow a_c = 141.96 \, \mathrm{m/s^2}\) So, the magnitude of the acceleration of a point on one of its blades \(10.0 \, \mathrm{cm}\) from the axis of rotation is approximately \(141.96 \, \mathrm{m/s^2}\).

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Key Concepts

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

Angular Velocity
Angular velocity is a measure of how fast an object rotates or revolves relative to another point, usually the center of a circle. Imagine a fan blade spinning; the speed at which the blade spins around the fan's center is its angular velocity. It's usually denoted by the Greek letter \(\omega\) and is a vector, meaning it has both a magnitude and a direction. In physics problems, we often discuss angular velocity in terms of radians per second (rad/s), where a radian is the angle subtended by an arc equal in length to the radius of the circle.

In our exercise, the angular velocity is essential for determining the centripetal acceleration. To calculate it from revolutions per minute (rev/min), as given in the fan scenario, we need to convert these units into radians per second. This involves multiplying by 2Ï€ to convert revolutions to radians and then dividing by 60 to convert minutes to seconds.
Rotational Motion
Rotational motion refers to the movement of an object around a fixed point or axis. This type of motion is omnipresent in daily life, from the wheels on a car to the rotations of a merry-go-round. It's crucial to understand that the faster the rotation or the greater the distance from the axis, the more substantial the effects of this motion on the object.

When studying rotational motion, we often encounter terms like centripetal force and acceleration, which are critical to keep an object moving in a circular path. The physics problem in our example focuses on calculating the centripetal acceleration, a direct result of rotational motion, at a specific point on a fan blade. The acceleration is directed towards the center of the rotation, keeping the blade on its circular path.
Radians Per Second
The unit 'radians per second' is the standard unit of angular velocity. It defines the rate at which an object rotates in terms of the angle (in radians) that it sweeps out per second. To clarify, a radian is a way of measuring angles based on the radius of a circle; it is roughly equivalent to 57.3 degrees and there are 2Ï€ radians in a full circle. Since the fan in our example goes around 360 degrees per minute, and since 360 degrees is equal to 2Ï€ radians, it can convert this easily into radians per second.

To convert revolutions per minute to radians per second, as in our exercise, you take the number of revolutions per minute, multiply by 2Ï€ to convert to radians (since there are 2Ï€ radians in one full revolution), and divide by 60 to convert minutes to seconds. This gives us a standard measure to use in subsequent calculations, like finding centripetal acceleration.
Physics Problem Solving
Physics problem solving often requires a step-by-step approach to break down complex concepts and calculations into more manageable parts. This approach is on full display in the fan blade exercise. We start by converting units to standard SI units (meters, seconds, etc.), a fundamental step for consistent calculations. We then piece together known concepts, like how to relate angular velocity to centripetal acceleration, and apply them to the specific scenario.

Such problems require attention to detail and process: from unit conversion, understanding the relevant formulas, to the execution of calculations. Applying this structured problem-solving method not only helps to arrive at the correct answer but also deepens one's understanding of the underlying physical principles involved.

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Most popular questions from this chapter

A rock is thrown off a cliff at an angle of \(53^{\circ}\) with respect to the horizontal. The cliff is \(100 \mathrm{m}\) high. The initial speed of the rock is \(30 \mathrm{m} / \mathrm{s}\). (a) How high above the edge of the cliff does the rock rise? (b) How far has it moved horizontally when it is at maximum altitude? (c) How long after the release does it hit the ground? (d) What is the range of the rock? (e) What are the horizontal and vertical positions of the rock relative to the edge of the cliff at \(t=\) \(2.0 \mathrm{s}, t=4.0 \mathrm{s},\) and \(t=6.0 \mathrm{s} ?\)

An airplane flying horizontally with a speed of 500 \(\mathrm{km} / \mathrm{h}\) at a height of \(800 \mathrm{m}\) drops a crate of supplies (see the following figure). If the parachute fails to open, how far in front of the release point does the crate hit the ground?

A ship sets sail from Rotterdam, heading due north at 7.00 \(\mathrm{m} / \mathrm{s}\) relative to the water. The local ocean current is 1.50 \(\mathrm{m} / \mathrm{s}\) in a direction \(40.0^{\circ}\) north of east. What is the velocity of the ship relative to Earth?

A small plane flies at \(200 \mathrm{km} / \mathrm{h}\) in still air. If the wind blows directly out of the west at \(50 \mathrm{km} / \mathrm{h}\), (a) in what direction must the pilot head her plane to move directly north across land and (b) how long does it take her to reach a point \(300 \mathrm{km}\) directly north of her starting point?

A Formula One race car is traveling at \(89.0 \mathrm{m} / \mathrm{s}\) along a straight track enters a turn on the race track with radius of curvature of \(200.0 \mathrm{m}\). What centripetal acceleration must the car have to stay on the track?

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