* Newton's Laws of Motion: Newton's First Law states that an object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

* Force = Mass x Acceleration: Newton's Second Law defines the relationship between force, mass, and acceleration. Acceleration is the rate of change of velocity (speed and direction).

* Examples:

* Pushing a box: You apply a force to the box, causing it to accelerate and change speed.

* Gravity: The force of gravity pulls objects towards the Earth, causing them to accelerate and change speed.

* Friction: Friction acts against motion, causing objects to slow down (change speed).

* Air Resistance: Air resistance opposes motion, slowing objects down (change speed).

In summary: A force causes an object to accelerate, and acceleration is the change in speed (or velocity).