Physics and Newton's Third Law of Motion

Newton's 3rd law states that for every action there is an opposite and equal reaction. Put another way when you push on an object it pushes you back.

Newton's 3rd law starts with conservation of momentum Conservation of momentum states  that the total change in a system’s motion to be zero. As a result moving a mass requires moving another mass in the opposite direction.

Rockets are the best example and the flame that is seen coming from the bottom of the rocket is propellant mass that is being ejected from the engines. This mass provides the action whose reaction pushes the rocket forward. Jets work on same basic principle but the main differ deference between a jet and a rocket is that jets take in air as part of their propellant mass making them more efficient than rockets since they are nor required to carry all that mass onboard.

The basic concept of Newton's 3rd law is that two masses push on each other with equal force. Equal mass will move away at the same speed. When one mass is smaller the other and if the force is kept the same, the smaller mass moves away faster and the heavier mass moves at the same speed as before. If one keeps the masses the same as in the last example but this time the force is larger then they both fly apart faster. The smaller mass still moves much faster than the larger mass.

One thing that is a little counter interactive is the fact that when a car that is being driven down the road, the Earth is actually being pushed in the opposite direction. To be fair this affect is extremely small but it is sill not zero and the traffic that is going opposite direction averages out to zero net force. It gets even stranger since even when you are just walking around you are actually pushing the Earth in the opposite direction. Once again it is still an extremely small, in fact much smaller than in a car; but still not zero. Furthermore all the people and animals in the world the affect will still average out to be zero. Like wise when a planet moves around its star the planet pulls back on the star causing it to wobble slightly. This is a main way that extra Solar planets are detected.  

Newton's 3rd law of Motion boils down to the fact that when one object pushes on another object, the second object pushes back. It is an important part of every change in motion in the universe because with out it no changes in motion would ever occur in the universe.

Newton's Laws of Motion They Really Move

The three basic physical laws of classical mechanics are called Newton's Laws of Motion. They describe the relationship between a body, the forces acting on it andhow that affects the resulting motion.

Newton's First law says a body will remain in rest or in motion unless acted on by an out side force. It is also known as the law of inertia since inertia is the resistance to changes in motion.

Newton's Second law says a mass acted on by a force undergoes acceleration in the direction of the force, with a magnitude inversely proportional to the mass and proportional to the force.

Formula

f = ma

f   = force

m = mass

a  = acceleration

Newton's Third law states that for every action there is an opposite and equal reaction.  Put another way when you push on an object it pushes you back. This is the bases of rockets and jets.

 These three laws along with gravity form the cornerstone of modern physics. Not much outside quantum mechanics makes since with out them. They affect every aspect of our lives and are involved in some way with every thing we do.

 The three laws are most evident in space flight. The 3rd law provides force to move a rocket, the 2nd law turns that force into acceleration and the 1st law keeps a space craft in obit or moving through deep space.

In conclusion Newton's Laws of Motion are the three basic physical laws of classical mechanics. They affect every aspect of our lives, in fact we use them every time we move.