When you lie down on a bed, you are exerting a force of weight on the bed.

Here's why:

* Gravity: Your body is constantly being pulled towards the center of the Earth by gravity. This force is known as your weight.

* Support: When you lie down on the bed, the bed provides a supporting force that counteracts your weight. This is what keeps you from falling through the bed.

So, while you are applying a downward force (your weight), the bed provides an upward force that balances it out.