Force and motion
Force and Motion
Locating the page positions
Attach the pop-up on both sides
The pop-up piece needs to be attached to the book on either side of the gutter. Why? If the pop-up is attached only to the left side, the pop-up piece won’t be anchored, so it will simply follow the left side as in Figure a). On the other hand, suppose it’s attached only on the right side, as in Figure b. When the book opens, the pop-up won’t follow it, because the force of the moving page won’t be transmitted to it. To achieve pop-up action, the pop-up piece has to be attached to both sides, because it needs to be both anchored to the fixed side, and pushed or pulled by the movable side, as shown in Figure c).