I had studied Physics during my Pre-University years, and I had scored some marks also in the subject. But it was later, when I had left all my contacts with the subject physics, that I got enchanted with this discipline. People tend to keep away from physics, but physics as a philosophy is pure enchantment, and nothing but pure joy.
I understood the philosophy of the Principle of Gravitational force recently only. I had studied the Newtons theory of Gravitational force during the days in college., but I understood what gravity was recently only. Had a question been asked, whether a stone or a feather dropped from the same height, will hit the ground first, I would’ve answered, instantly that, the stone will be the first to hit the ground. I am sure most of the people will answer the same. Well, I too agree, if the stone and feather was thrown from top of a building near you., that stone will hit the ground first. But., but if you do the same experiment on the moon, the amazing result is that, both the stone and the feather will hit ground at the same time. Needless to say, the experiment was conducted by the first men on the moon, and the results confirmed to Newtons Gravitational theory, which predicted that both will land at the same time!!!!!
Wonder why??!! Lets try to analyse the thoughts of Sir Issac Newton. Lets not waste time discussing whether the apple fell on Newtons head or near him., but we know that it did give newton impetus to think about the principle behind the fall. The gravitational thoery, which Newton brought about, mostly was based on the moon and its movement around earth. Let us common people, look at it this way. Any object has got a field of attraction. This field gets weaker as the distance from the object increases. Now since every object attracts, using apple as our example, we say that Apple attracts Earth, as Earth attracts the Apple. But since the mass of Earth is much much greater than the apple, the attraction is fatal for apple which falls towards earth. Now lets imagine apple is in outerspace, beyond our atmosphere, still earth attracts it and apple also attracts earth.. but since the distance between both has increased, the attraction is weak. but given time, eventually, this attraction moves the lighter object towards the heavier object and the apple will eventually fall towards earth. So you may ask, will moon fall into earth eventually.. yes.. but dont worry, when it will happen, humans might have colonised other solar systems., ie it will take a long time for that to happen.
Now lets come back to the experiment of the stone and the feather.. Why does both fall together at the surface of the moon, when dropped from same height. you will say, that the stone has got more mass and hence it should reach the surface first and then the feather should reach the ground. Hmm.. here comes the shift in thinking. Defenitely the gravitational force applied on the stone is greater than the gravitational force on the feather. But… understand this, more force is required for the stone to move towards the ground at the same rate as the feather and hence both fall at the same rate. Didnt get the point.. Think about it. This is the wonder of physics.
Didnt get it yet… I will illustrate with an example. say you have got a 20 kilo stone on the ground, and a feather, both which you have to lift up simultaneously, You will have to apply heavy force on the stone, than on the feather to lift it up, where as you need apply only a little force to lift the feather up. Now think about the same with gravitational force.. the same principle applies there.. Even if the gravitational force is more on the stone, its required to move the stone at the same rate as which the feather is attracted. If you understand this.. you will be wonder at the marvel that is physics.
Issac Newton made this discovery, but we all need to discover it again, to understand the Wonder of the nature, the principle of Gravity.