**a)**

Angular speed:

ω = 2π/T

The earth's radius is 6.37 x 10^{6} m; it rotates once every 24 hours.

a) What is the earth's angular speed?

b) Viewed from a point above the north pole, is the angular velocity positive or negative?

c) What is the speed of a point on the equator?

d) What is the speed of a point on the earth's surface halfway between the equator and the pole? (Hint: what is the radius of the circle in which the point moves?)