A projectile is shot directly away from Earth's surface. Ignore the rotation of Earth. What multiple of Earth's radius RE gives the radial distance a projectile reaches if
(a) its initial speed is 0.500 of the escape speed from Earth and
(b) its initial kinetic energy is 0.500 of the kinetic energy required to escape Earth?
(c) Find the least initial mechanical energy required at launch if the projectile is to escape Earth, if the projectile has a mass M?