Newton's 3 Laws of Motion
The first law of motion is that an object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and same direction unless acted upon by an unbalanced force. This law is often called "the law of inertia". In other words, if an object is not moving unless a stronger force is applied to the object. If an object is in motion, then it will stay in motion, at the same speed and same direction (same rate), unless a force is applied to stop it.
This picture is an example of inertia. The statue won't move unless a stronger force like a tornado or something moves it. An example of inertia that could be done in the classroom is if I am walking until I get at the counter than I can't walk anymore.
The second law of motion states that acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object. In other words, an object with a higher mass needs more force to accelerate. Acceleration is the speed and direction.
The woman needs to apply a force for the stroller to move. So this is an example of it. I could move somebody's binder then move pencil. The binder would need more force therefore demonstrating it.
The third and final law of motion states that for every action there is an equal and opposite reaction. In other words, when something moves, then something else pushes on it with an equal reaction.
The picture explains how the force that the ball its the other ones with makes an equal and opposite force. I could push someone while they push me too. This would work because someone would press against me with the same force, yet whichever object has a smaller mass will go back farther