3) The equator of the earth is approximately a perfect circle (imagine looking down onto the north pole). For objects at the equator, the earth's natural rotation creates a linear speed of approximately 1000 mph. a. Use this information to find the approximate radius of the earth. (Hint: you know the angular speed of earth...) b. Suppose you took a trip 3000 miles along the equator. What central angle of the earth did your trip cover?