# Math Help - Angular and linear velocity problem...

1. ## Angular and linear velocity problem...

To get linear velocity isnt the radius multiplied by the angular velocity in order to get linear velocity? Im lost I keep getting the wrong answers. For angular velocity I got 1,803,600 radians/hour and for linear velocity I got 23,741, 676 miles/hour. I dont get it.

The problem is: The radius is 21.910 inches. A wheel rotates 150.5 times per second. I need to find:

1. The angular velocity in radians/hour.
2. The linear velocity in miles/hour.

2. Originally Posted by princesasabella
To get linear velocity isnt the radius multiplied by the angular velocity in order to get linear velocity? Im lost I keep getting the wrong answers. For angular velocity I got 1,803,600 radians/hour and for linear velocity I got 23,741, 676 miles/hour. I dont get it.

The problem is: The radius is 21.910 degrees. A wheel rotates 150.5 times per second. I need to find:

1. The angular velocity in radians/hour.
2. The linear velocity in miles/hour.
There are 3600 seconds in an hour, and $2\pi$ radians in a revolution, so the angular velocity will be $150.5\times2\pi\times3600$ radians/hour.

Whatever the radius is measured in, it certainly won't be degrees. You need to check what the units are for the radius, and then convert them into miles. Then multiply that by the angular velocity and you'll get the answer in miles/hour.