Whoopi Goldberg's comedy, "Jumpin' Jack Flash," is the hot new rental, climbing to No. 6 on the Billboard magazine chart in just two weeks. It's the likely successor to 'The Color of Money," which remains the No. 1 rental. "Children of a Lesser God" (No. 2) and "Heartbreak Ridge" (No. 3) also have a good shot at the top rental slot. Impressive rental chart debuts: "The Morning After" (No. 11) and "The Mosquito Coast" (No. 12); the former, featuring Jane Fonda's acclaimed performance, has Top Five potential. "Mona Lisa" (No. 18) and "Wanted Dead or Alive" (No. 22) have had only fair rental success. The best-selling cassette is still "Top Gun." Other sales charts: "Sleeping Beauty" is the leading kidvid cassette, while "Jane Fonda's Low Impact Aerobic Workout" and "Jane Fonda's New Workout" head the health and fitness chart.