get cracking/rolling

get cracking

To start working on something. Often used as an imperative. Get cracking, or you'll be up all night working on your book report! Let's get cracking—I don't want to spend all day cleaning out the garage.
See also: cracking, get

get rolling

To leave or depart. Let's get rolling. We need to be at the airport by 7:30. There's nothing happening here—let's get rolling.
See also: get, roll
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

get rolling

Fig. to get started. Come on. It's time to leave. Let's get rolling! Bill, it's 6:30. Time to get up and get rolling!
See also: get, roll
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

get cracking/rolling

Begin, get busy, hurry up. The first of these colloquialisms originated in Great Britain in the 1930s and appears to have crossed the Atlantic during World War II. It uses crack in the sense of “move fast,” a usage dating from the late nineteenth century, and is often put as an imperative, as in “Now get cracking before it starts to rain.” The synonymous get rolling, dating from the first half of the 1900s, alludes to setting wheels in motion. It, too, may be used as an imperative, but is more often heard in such locutions as “Jake said it’s time to get rolling on the contracts.”
See also: cracking, get, roll
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
See also: