* Gravity: This is a fundamental force that pulls objects towards each other, and it always acts on everything with mass.
* Friction: This force opposes motion between surfaces in contact. It can act whenever an object is sliding or rolling across another surface.
* Elastic forces: These are forces that arise when an object is deformed, like a spring being stretched or compressed.
Example:
Imagine a rubber ball bouncing on the floor. Here's how the forces work:
* Gravity: Always pulling the ball down towards the earth.
* Friction: Acts between the ball and the floor as it rolls, slowing it down.
* Elastic forces: Come into play as the ball compresses upon hitting the floor, then pushes back, causing the bounce.
Important Note: These forces can sometimes be in balance, leading to an object staying still or moving at a constant velocity. But often, they are unbalanced, resulting in acceleration (changing velocity).
