* Newton's First Law of Motion: 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.

* Newton's Second Law of Motion: The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This means:

* Acceleration requires a force: If you want an object to speed up, slow down, or change direction (all of which involve changing speed), you need a force to cause that acceleration.

* The bigger the force, the bigger the acceleration: A larger force produces a larger change in speed over a given time.

* The heavier the object, the smaller the acceleration: A more massive object will accelerate less for a given force.

Examples:

* Pushing a cart: You need to apply force to the cart to make it move (change speed from rest to moving) or to make it go faster (increase speed).

* Stopping a car: The brakes apply a force to slow down the car (decrease speed).

* Turning a corner: A force is needed to change the car's direction, which also involves a change in speed.

In Summary: Forces are the agents of change for motion. To alter an object's speed, you must apply a net force.