The simple machine that changes the direction over which force is exerted is a pulley.

Here's why:

* How it works: A pulley is a wheel with a groove around its rim, designed to support a rope or cable. When you pull on one end of the rope, the pulley redirects the force to the other end of the rope.

* Example: Imagine lifting a heavy object with a rope. If you pull directly upwards, you need to exert a lot of force. But, if you use a pulley attached to the object, you can pull downwards on the rope, and the pulley will redirect that force upwards to lift the object.

Let me know if you'd like more details about how pulleys work!