To understand what force is applied when something increases, we need to know:

* What is increasing? Is it pressure, speed, mass, tension, etc.?

* What is the system or object involved? Is it a gas in a container, a car on a road, a rope pulling a weight, etc.?

For example, if you say:

* "What force is applied when the pressure in a container increases?"

* "What force is applied when the speed of a car increases?"

Then I can give you a meaningful answer.

Please clarify your question. 😊