3. In an idealized model of the path of a rocket launched from Earth, the Earth is a sphere with equation x2 + y? + = = (6000km) and the parametric vector function that describes the path of the rocket is r(t) = . Note that at t = 0, the rocket is on the surface of the (idealized) Earth. (a) At what time has the rocket travelled 24, 000kms? (b) How far from the Earth is the rocket at that time