What will drop "faster" to the ground? A KG Feathers or a KG Steel?

Question

Do some items drop faster than others and if so why?

Answer 1

In a vacuum both will drop at the same rate.

As part of the Apollo moon missions one of the astronauts did this with a hammer and a feather.

http://nssdc.gsfc.nasa.gov/planetary/image/featherdrop_sound.mov

If you put them in containers the same size they will drop at the same rate.

If you drop them in air, and they have different drag coefficients then air resistance on each will be different and they will fall at different rates.


BTW, they do not have to be the same mass. 0.1 g of feathers will drop at the same rate as 1000 tonnes of steel if the air resistance is the same.


This assumes that you are dropping all these objects at the same point on the same planet. If you drop one on the moon and one on the Earth at the same time, then, ignoring air resistance on the Earth, the one on the Earth will hit the ground first due to the stronger gravity field. Since there very slight variations in gravity, you could drop two identical objects at the same time in different places and one could hit a few nanoseconds before the other.

Answer 2

Reene has basically got it. If they are in the exactly the same bag (same air resistance)they fall at the same speed. It doesn't matter how much they weigh.

Newton may have formulated the law mathematically but it was Gallileo who supposedly proved it experimentally. Until that demonstration from the leaning tower of Pisa people thought (or were supposed to think) that things which were 5 times heavier fell five times faster, because Aristotle said so.

So really the law of Gravity is almost too easy to believe and in fact a lot of modern physics is concerned with finding out if it is this simple. However if it isn't, the difference is not something that we would easily notice

Answer 3

Dude...it just depends on the amount of air resistance encountered by the objects...in open,if the steel has more surface area to encounter the air drag than the feathers, than the feathers will reach the ground first.otherwise steel...however in vacuum, both will reach the grnd at da same time since no air resistance is present.
u can also have another view this way: h= ut+1/2*g*t^2. hence t depends on h and g. and since h and g are same for feathers as well as steel, they should reach the ground at same time, if we dont count air resistance....hope its clear

Answer 4

Depends if you drop the feathers one at a time. A solid bag full of feathers weighing a kg wll fall at the same rate as a kg of steel. (the density difference will not noticeably effect the acceleration if the bag is soildly packed with feathers).

Due to gravitational forces all things will fall at the same rate -- such was demonstrated by Newton, I think!

However - when something is very light so that the natural forces of wind/air and/or thermal currents can affect its transit through the air it will not fall directly to the ground.

QUOTE:
"Under normal Earth-bound conditions, when objects move owing to a constant gravitational force a set of kinematical and dynamical equations describe the resultant trajectories. For example, Newton’s law of gravitation simplifies to F = ma, where m is the mass of the body and a is the acceleration. This assumption is reasonable for objects falling to Earth over the relatively short vertical distances of our everyday experience, but does not necessarily hold over larger distances, such as spacecraft trajectories, because the acceleration far from the surface of the Earth will not in general be g which is acceleration due to gravity (9.8 m/s2). A further example is the expression that we use for the calculation of potential energy Ep of a body at height h ( Ep = mgh or as Ep = Wh, with W meaning weight). This expression can be used only over small distances h from the Earth. Similarly the expression for the maximum height reached by a vertically projected body, h = u2 / 2g is useful for small heights and small initial velocities only. In case of large initial velocities we have to use the principle of conservation of energy to find the maximum height reached"

Answer 5

It's not going to be very scientific and I'm sure someone will come up with the whole theory behind it but steel falls faster than feathers because the air stopt the feathers from falling as fast because they catch it and float on it. If we had the same gravity but no atmosphere then everything would fall at the same rate.

Answer 6

A kilogram of feathers and a kilogram of steel both weigh the same amount (one kilogram). Although the kilogram of feathers will be FAR larger than the kilogram of steel, it both are wrapped tightly (to avoid air resistance from the feathers) and dropped simultaneously, both will reach the ground at the same time.

Answer 7

Steel - Less air resistance


In a vacuum - same speed for both

Answer 8

well......a kg steel ...will drop faster...since its density is higher than that of a kg feather.....so the friction offered by air is overcomed easily by steel...but doing that, is difficult for feather....so it reaches d ground late.......

Answer 9

you may by no skill attain the precise of the fence on the roof. the protection gurards could have you ever on the floor precise away flat. flow to the precise of the Chrystler construction somewhat.

Answer 10

they both hit the ground at the same time