What is "in gear"

Usage examples of "in gear".

And she can barely decide to get out of bed in the morning, but she gets in gear, orders a droid to ditch her dead husband's body, and gets it done in the time it takes you to get her a glass of water.

And she was going to be both unprepared and late if she didn't get her butt in gear.

Roy DeLois put his cab in gear and drove away, leaving Bobby in front of the Wo Fat Noodle Company.

And if you don't get that bony ass in gear, she's going to kick it to New Jersey when she gets back.