Most apps implement simple animations, like the ones you saw in the last couple of sections. However, some animations might need even more realism. This is what UIKit Dynamics is for. With UIKit Dynamics, you can place one or more views in a scene that uses a physics engine to apply certain forces to the views it contains. For instance, you can apply gravity to a particular object, causing it to fall off the screen. You can even have objects bumping into each other, and if you assign a mass to your views, this mass is taken into account when two objects crash into each other. When you apply a certain force to an object with very little mass, it will be displaced more than an object with a lot of mass, just like you would expect in the real world.
Let's take a little break from building Hello-Contacts and use a separate app to implement a nice, little physics experiment! Create a new project and name it Cradle. Make sure to configure the project so it only...