Verified answer

a) Assuming the earth is a sphere, the circumference is 2*π*r = 2*( 3.1416 )*6.37*10^6 = 40.0*10^6 m

Since it rotates a complete circle once every 24 hours, the rim velocity is:

v = 40.0*10^6/(24*60*60) = 463.2 m/s

The centripetal acceleration is:

a = v^2/r = 463.2^2/6.37*10^6 = .0337 m/s^2

b) At the North Pole, the rim velocity would be zero, since the axis of rotation passes through the North Pole, so the centripetal acceleration would also be zero.