Wednesday, 28 October 2015

gravity - Free falling of object with no air resistance




Why does an object with smaller mass hits the ground at same time compared to object with greater mass? I understand the acceleration due to gravity of earth will be same but won't the object with greater mass will fall faster?



Answer



That is an excellent example for a nice quote I read on the internet: "Common sense may be common, but it certainly isn't sense" :-)


As it is hard to lift heavy objects, we assume that it must be easier for them to drop.


Now, Newton's laws point out that light and heavy objects will fall with the same velocity. But is there an intuitive reason? Yes!


The mass of an object contributes to two different phenomena: Gravity and inertia.



  • The heavier an object is, the stronger the gravitational pull it experiences.

  • The heavier an object is, the stronger its resistance to an accelerating force will be: Heavier objects are harder to set in motion, meaning that for the same acceleration you need a larger force.



When people think that heavy objects should fall faster, they only think of the first point. But in reality, the first and second point cancel out each other: Yes, the earth pulls stronger on a heavy object, but the heavy object is more reluctant to get moving.


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