5.6 x 2 = 11.2

11.2

In "Star Trek," the original series, there was a background tape of intercom chatter they loved to play whenever ... well, whenever they wanted some background intercom chatter; and a man's voice would say, "Gravity is down to ...". The answer to your question is that number subtracted from the number of years between Pon'Fars for a Vulcan + the number of letters in Ensign Chekov's first name.

11.2 (56*20/100)