# Angular Speed.....

• October 7th 2008, 11:49 AM
Brndo4u
Angular Speed.....
Find the angular speed of a point on the earth surface. That is all that is given, assume that Radius is 6400km. how do I set this up.
• October 7th 2008, 01:39 PM
skeeter
angular velocity is the same for all points on the earth except the poles.

$\omega = \frac{1 \, revolution}{day}$
• October 7th 2008, 02:15 PM
Soroban
Hello, Brndo4u!

There is either too much information or insufficient information.

Quote:

Find the angular speed of a point on the Earth's surface.
Assume that radius of the Earth is 6400 km.

Every point on the Earth, except the two poles, turns though 360° every 24 hours.

. . Hence, the point moves: . $\frac{360}{24} \:=\:15\text{ degrees per hour.}$

And the radius of the Earth is irrelevant.

If the speed is to be in kilometers per hour,
. . we should have been given the latitude of the point.

Assuming that point is on the Equator,
. . the circumference is: . $2\pi\cdot6400 \:\approx\:40,\!212.4$ km.

Then the point moves at: . $\frac{40,\!212.4}{24} \:\approx\:1675.5$ km/hr.