Argelia has a stack of schoolbooks sitting in the backseat of her car. When Argelia makes a sharp right turn, the books slide to the left of the seat until they come to a rest against the car door. Explain why this happens.

The phenomenon is caused by the term "Angular momentum".

When she makes a sharp right turn, the book itself has a relative acceleration to the left tangentially. In other words, without the door blocking the books, the book will be thrown tangentially to the left, due to the momentous angular velocity.