Newton's First Law of Motion also called the Law of Inertia
The frisbee or object, thrown by the boy, is currently in motion without any outside force being applied to it.
The frisbee has now been put out of motion by an unbalanced force or the dog/dog ctching it.
Newton's First Law States: If an object is at rest OR moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at a constant speed unless acted upon by an unbalanced force. But if acted on by a balanced force it will continue to stay at rest OR in motion since this force is within balance or the same as the object's motion/rest.
Newton's Second Law of Motion
Phew! I'm pushing these pieces of furniture with the same amount of force. So why is the dresser moving so much slower than the stool?
Newton's Second Law States: The acceleration of an object depends on its mass and the net force
Well no wonder! The dresser has a greater mass compared to the stool, so it moves with less acceleration.
Newton's Third Law of Motion
Ugh! Why does she keep flying into me?!
Newton's Third Law States: For every action, there is an equal and opposite reaction.
As the girl is swinging, gravity helps pull her back down toward the ground or to her starting point.
Ohhh, the force I'm using to push her is equal, and she's coming back as an opposite force.