Aristotle believed that natural motion required no forces. This concept is closely tied to his view of the cosmos, which he believed was composed of four elements: earth, water, air, and fire. Each element had a natural place in the universe:

* Earth naturally moved downwards, towards the center of the universe.

* Water naturally moved downwards, but less forcefully than earth.

* Air naturally moved upwards, away from the center.

* Fire naturally moved upwards, even more forcefully than air.

Therefore, for Aristotle, objects made of these elements would move naturally towards their "natural place" without the need for any external force.

Here are some examples of natural motion according to Aristotle:

* A rock falling to the ground.

* Smoke rising into the air.

* A bubble floating upwards.

Aristotle also believed in violent motion, which was caused by an external force. Examples of violent motion include:

* Pushing a cart.

* Throwing a ball.

* Pulling a rope.

It's important to note that Aristotle's ideas about motion were later proven incorrect by scientists like Galileo and Newton. However, his theories were influential for centuries and laid the groundwork for later scientific inquiry.