Set in motion and Set up

Set in motion verb - Get going; give impetus to.

Set up and set in motion are semantically related. in start topic. In some cases you can use "Set up" instead a verb phrase "Set in motion", when it comes to topics like begin, initiate, create.

Set up verb - To arrange something in a certain spot or position.

Set in motion and set up are semantically related. Sometimes you can use "Set in motion" instead a verb "Set up".