A projectile is shot directly away from Earth's surface. Ignore the rotation of the Earth. Find what multiple of Earth's radius RE gives the radial distance (from the Earth's center) the projectile reaches if
(a) its initial speed is 0.709 of the escape speed from Earth and
(b) its initial kinetic energy is 0.709 of the kinetic energy required to escape Earth?
(c) Find what least initial mechanical energy required at launch if the projectile is to escape Earth?