Newton's Third Law of Motion:
Every action has an equal and opposite reaction
Quick Review on Newton's Third Law of Motion
Newton's third law states that for every action, there is an equal and opposite reaction. Forces come in pairs, which are called action and reaction. Newton's third law explains how for every interaction between two objects, there is a pair of forces acting with the same size force, but in opposite directions. Newton's third law can be related to a very specific part of a bungee jumping system. That is, the point in which the bungee is completely stretched out and the jumper is actually at rest. At this specific point, where the bungee is stretched out and the jumper is about to be sprung back upwards. The mass of the earth exerts a gravitational force on the mass of the jumper, while at the same time the bungee reacts by exerting an opposite but equal force. With these two opposite but equal forces in balance with eachother, the object that the forces are being exerted on, in this case the jumper, is at rest.
NET FORCE= F(bungee)-F(earth)=0
At the point in which the bungee cord is completely stretched out, the object that once was in motion is at rest. This is a very short amount of time, but for that very second, the object is at rest due to the fact that the two forces acting on the object are balanced; that is, the force of gravity, and the force of the bungee itself. The forces acting on the object are equal in size, but opposite in direction.
Newton's third law can also be applied to the entire bungee jumping system. This law can be applied as the bungee jumper is falling. A common misconception often found in Newton's third law is, "if the forces are supposedly the same, why is it that the bungee jumper is accelerating downwards?"
The answer is because of mass. As explained in Newton's first law, mass has a great impact on bungee jumping. The two masses in the bungee jumping system are the earth and the bungee jumper. Obviously, the bungee jumper weighs a little bit less that the earth....actually a lot less!! For learning purposes, lets call the bungee jumper Mass A. As the earth, Mass B, exerts a gravitational force on Mass A, Mass A reacts through the equal in size, opposite in direction, restoring force of the spring. Because of this huge difference in mass, even though the same size force is applied by the earth and the spring, the force from the earth has a much greater impact. Newton's Second Law tells us that Force=(mass)(acceleration). Hypothetically, if we were to create two situations, both in which have the same amount of force, but much different masses, we would see that acceleration changes dramatically. Force is inversely proportionate to mass, therefore the objects with a greater mass, need a greater acceleration to move. The mass of the bungee jumper is insanely less than the mass of the earth, therefore with the same force applied, the acceleration of the bungee jumper is far greater than the acceleration of the earth, which is why the bungee jumper accelerates downwards.
The answer is because of mass. As explained in Newton's first law, mass has a great impact on bungee jumping. The two masses in the bungee jumping system are the earth and the bungee jumper. Obviously, the bungee jumper weighs a little bit less that the earth....actually a lot less!! For learning purposes, lets call the bungee jumper Mass A. As the earth, Mass B, exerts a gravitational force on Mass A, Mass A reacts through the equal in size, opposite in direction, restoring force of the spring. Because of this huge difference in mass, even though the same size force is applied by the earth and the spring, the force from the earth has a much greater impact. Newton's Second Law tells us that Force=(mass)(acceleration). Hypothetically, if we were to create two situations, both in which have the same amount of force, but much different masses, we would see that acceleration changes dramatically. Force is inversely proportionate to mass, therefore the objects with a greater mass, need a greater acceleration to move. The mass of the bungee jumper is insanely less than the mass of the earth, therefore with the same force applied, the acceleration of the bungee jumper is far greater than the acceleration of the earth, which is why the bungee jumper accelerates downwards.