Planet X has mass 4.0×1024kg and radius 4.0×106m. Planet Y has the same average density as Planet X but a radius of 8.0×106m.
a. (i) Calculate the acceleration due to gravity at the surface of Planet X. (Use G=6.67×10−11N m2/kg2.)
b. (ii) Calculate the acceleration due to gravity at the surface of Planet Y.