Picture!

In this photo, Megan is hitting a book out from under a water bottle. The water bottle falls straight down rather then flying in the direction that Megan hit the book. This is so because of Newton's first law of Inertia. This law states that an object in moition will stay in motion or an object at rest will stay at rest unless a force is exerted upon it. The water bottle is at rest and wants to stay at rest, so when the book below it is hit, the water bottle stays put until the force of gravity pulls it down.