Here's a breakdown:

* Compressive force: Pushes on an object, causing it to shorten or become squeezed. Think of a stack of books being pressed down.

* Tensile force: Pulls on an object, causing it to stretch or lengthen. Think of a rubber band being pulled.

These forces are opposites because they have opposing effects on the object:

* Compressive forces cause compression (a decrease in length).

* Tensile forces cause tension (an increase in length).

Let me know if you'd like more examples!