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Ch 04: Kinematics in Two Dimensions
Chapter 4, Problem 4

The earth's radius is about 4000 miles. Kampala, the capital of Uganda, and Singapore are both nearly on the equator. The distance between them is 5000 miles. The flight from Kampala to Singapore takes 9.0 hours. What is the plane's angular velocity with respect to the earth's surface? Give your answer in degrees/h.

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1
Calculate the angular displacement in radians by using the formula: \( \theta = \frac{\text{arc length}}{\text{radius}} \). Here, the arc length is the distance between Kampala and Singapore, and the radius is the Earth's radius.
Convert the angular displacement from radians to degrees. Recall that \( 1 \text{ radian} = \frac{180}{\pi} \text{ degrees} \).
Determine the time duration of the flight in hours.
Calculate the angular velocity in degrees per hour using the formula: \( \omega = \frac{\theta}{\text{time}} \), where \( \theta \) is the angular displacement in degrees and time is the duration of the flight in hours.
Interpret the result as the plane's angular velocity with respect to the Earth's surface in degrees per hour.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Angular Velocity

Angular velocity is a measure of how quickly an object rotates around a specific point or axis. It is typically expressed in degrees per unit of time, such as degrees per hour. In this context, it describes how fast the plane is moving in relation to the Earth's rotation as it travels from Kampala to Singapore.
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Circumference of the Earth

The circumference of the Earth can be calculated using the formula C = 2πr, where r is the radius. Given the Earth's radius of about 4000 miles, the circumference is approximately 25,132 miles. This value is essential for determining the relationship between linear distance traveled and angular displacement during the flight.
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Linear vs. Angular Motion

Linear motion refers to movement along a straight path, while angular motion involves rotation around a point. In this scenario, the plane's flight path can be analyzed in terms of linear distance (5000 miles) and converted to angular motion to find the angular velocity. Understanding this distinction is crucial for solving the problem accurately.
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