 Welcome to the video, Converting Rotational Velocity to Linear Velocity. In mechanics, the velocity of rotational devices, such as drive shafts, is often stated in revolutions per minute, or RPM. Although the circles below may have the same RPM, their linear velocities will be different because their circumferences are different. Linear velocity is distance traveled per unit of time, such as minutes or seconds. In the following examples, revolutions per minute will be converted to a linear velocity, stated in feet per minute. To convert rotational velocity to linear velocity, we must first calculate the circumference of each circle. Circumference is equal to 2 times pi times the radius, or pi times the diameter, as shown below. After calculating the circumference of each circle, determine the linear velocity by multiplying the circumference of each circle by the RPM. Remember, to convert from inches to feet, divide by 12. Now, test your scale in converting rotational velocity to linear velocity with the following three questions. When calculating, use the pi button on your calculator rather than 3.14. Also, don't round until the last step. Pause the video if you need more time to solve the problems. What is the linear velocity for a circle with a radius of 19 inches, rotating at 1,466 rpms? The answer is 14,584 feet per minute. What is the linear velocity for a circle with a radius of 3.1 inches, rotating at 478 rpms? The answer is 776 feet per minute. What is the linear velocity for a circle with a radius of 19.1 inches, rotating at 1,346 rpms? The answer is 13,461 feet per minute. Congratulations! You have completed this video, converting rotational velocity to linear velocity.