Newton’s Laws of Motion

      Newton’s first law of motion is often called the Law of Inertia. This law states 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 in the same direction unless acted on by an unbalanced force.” This means that unless an object is acted upon by an external force it will continue to do what it was previously doing, whether that be remaining idle or moving in a certain direction with a certain, constant magnitude.
      Newton’s second law refers to what makes up a force. This law states that “Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater amount of force needed (to accelerate the object)." From this law came the equation F=MA which stands for Force is equal to the mass of an object multiplied by its acceleration. Through this equation we are able to deduce the force needed to move an object at a given acceleration. Newton’s second law means that the heavier an object is, the more force will be needed to move it.
      Newton’s third law introduces a concept that is very difficult for most humans to accept. His third law states, “For every action there is an equal and opposite reaction." This means that when a force is exerted on an object, that object pushes back with the same amount of force, but in the opposite direction. The reason this is such a hard concept to grasp is because if I push against an object and it pushes against me with the same magnitude the two forces should cancel each other out, but the object still moves. This is ultimately because when you exert a force on an object there is more than just that force being exerted on, there is a system of forces and masses that when combined the object moves.

Image from http://ffden-2.phys.uaf.edu/211_fall2004.web.dir/saul_alvarez/Law_of_Universal_Gravitaion.html