Earth's Rotational SpeedDate: 6/24/96 at 13:51:57 From: Anonymous Subject: Label for Earth's Rotational Speed Should the Earth's rotational speed be referred to in Revolutions per... or as some refer to it, in mph? I am asking because it doesn't seem to make a lot of sense to refer to it as a measurement of distance traveled, as my teacher likes to refer to it. Please help settle this argument. Thanks a lot - Tony Date: 6/24/96 at 14:24:2 From: Doctor Tom Subject: Re: Label for Earth's Rotational Speed It usually makes much more sense to speak in terms of revolutions per hour or some such units, because the rotation speed in terms of a velocity (mph or something similar) depends on the latitude. At the poles, the velocity is zero; at the equator of the earth, it's about 1000 miles per hour. In Seattle (about 45 degrees up), the speed is 1000*cos(45) miles per hour. But it's perfectly correct to say the rotation speed at the equator is X miles per hour, since you can work out other speeds (or angular speeds) from this. In physics, angular velocity is measured in terms of angle/time (rotations per hour, or something like that). That's because the equations used to relate torque, angular momentum, moment of inertia, and angular velocity must use those units. -Doctor Tom, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/