Newton's 3rd Law

Newton's 3rd Law states that, "for every action there is an equal and opposite reaction." In the video, I learned that when the force of gravity is pulling down on you, you are simultaniously pulling up on the force of gravity. I also learned that in an action reaction pair, the forces will always be equal. However, if the larger the mass of the object, the smaller the acceleration of that object will be. Therefore, if the acceleration of the the object is larger, the mass will then be smaller. To demonstrate this he showed a person who's mass was 50 Kg, in deep space, pushing on a basketball who's mass was 1 kg. Then using the formula F=ma, which is Newton's second law, he gets the acceleration of the object. Now, Newton's Second Law states that," acceleration is directly proportional to force and acceleration is inversely proportional to mass. In Formula form that looks like a=F/m or f=ma. That is why the acceleration of the person was 1/5 m/s^2 while the acceleration of the basketball was 10m/s^2.