What is the linear speed of a point on the equator, due to the earth's rotation?

The equatorial radius of the earth is
r = 6378 km = 6378 x 10³ m

The earth makes 1 revolution in 24 hours.
The angular velocity is
ω = (2π rad)/(24*3600 s) = 7.2722 x 10⁻⁵ rad/s

The tangential velocity (linear velocity) at a point on the equator is
v = rω
   = (6378 x 10³ m)*(7.2722 x 10⁻⁵ rad/s)
   = 463.8 m/s

463.8 m/s