[" 15.Distance of the centre of mass of a solid uniform cone from its vertex is "z_(0)" .If the radius of its base is "R" and its height is "],[h" then "z_(0)" is equal to "],[[" (1) "(3h)/(4)," [JE MAIN - 2015] "],[" (1) "," (2) "(5h)/(8)," (3) "(3h^(2))/(8R)," (4) "(h^(2))/(4R)]]