Distance between Cities Find the distance in kilometers between each pair of cities, assuming they lie on the same north-south line. Assume the radius of Earth is 6400 km. See Example 2. Panama City, Panama, 9° N, and Pittsburgh, Pennsylvania, 40° N
Ch. 3 - Radian Measure and The Unit Circle
Chapter 4, Problem 25
Use the formula v = r ω to find the value of the missing variable.
v = 12 m per sec, ω = 3π/2 radians per sec
Verified step by step guidance1
Identify the given variables and the formula: the formula is \(v = r \times \omega\), where \(v\) is the linear velocity, \(r\) is the radius, and \(\omega\) is the angular velocity.
From the problem, you have \(v = 12\) m/s and \(\omega = \frac{3\pi}{2}\) radians per second. The missing variable is \(r\) (the radius).
Rearrange the formula to solve for \(r\): \(r = \frac{v}{\omega}\).
Substitute the known values into the rearranged formula: \(r = \frac{12}{\frac{3\pi}{2}}\).
Simplify the expression by dividing 12 by \(\frac{3\pi}{2}\) to find the value of \(r\).

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Linear Velocity (v)
Linear velocity refers to the speed at which a point on a rotating object moves along its circular path. It is measured in units like meters per second (m/s) and depends on both the angular velocity and the radius of the rotation.
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Angular Velocity (ω)
Angular velocity measures how fast an object rotates or spins, expressed in radians per second (rad/s). It represents the rate of change of the angular displacement and is crucial for relating rotational motion to linear motion.
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Relationship Between Linear and Angular Velocity (v = rω)
The formula v = rω connects linear velocity (v), radius (r), and angular velocity (ω). It shows that linear velocity is the product of the radius of the circular path and the angular velocity, allowing calculation of any one variable if the other two are known.
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