a kilogram of feathers or a kilogram of iron? '

Which weighs more: a kilogram of feathers or a kilogram of iron? '

Hint: "They dont weigh the same" :D

21 Answers

62
Lokesh Verma ·

not exactly..

There is a difference between mass and weight.. (and this is a question i remember we had in our class IX book ;) )

6
AKHIL ·

i think they shud weigh same in vacuum....

11
Gone.. ·

bhaiya shud'nt they weigh the same as both are a kilo each ??

1
ronit muduli ·

They both weigh the same. Their mass is same i.e 1kg hence gravitational force acting on them would be the same if both are placed in the same heavenly body. Moreover, inertia would also be the same for that reason.

11
Soham Mukherjee ·

Yes,in vacuum it would tilt to the feather side....can anyone give the explanation...plz...i can't make out it....

1
mkagenius ·

i mean hollow sphere with air trapped in.

1
mkagenius ·

thats seems reasonable.....
good.
thats the way to look at things.
all round approach.

also if iron is moulded into a ball of rather large diameter...then...what to say...hehe... :P

106
Asish Mahapatra ·

I would like to ask one more question regarding why COM of feathers will be higher..

It is not necessary as we can spread out the feathers to have less thickness and we can also ensure that its COM lies below the iron block also..

The reverse can also be done...

The system can also be arranged in such a way that the heights of COMs coincide.

Then the main reason will be the buoyant force only

1
cute_cat ·

why should it be tilting towards the feather side in a vacuum?

11
Soham Mukherjee ·

in vacuum..there will be no buoyant force..so it should tilt towards the feather side...ya...it was asked to me in a quiz contest and i got it wrong..but the explanation is too much confusing to me...

62
Lokesh Verma ·

Shreyan has assumed that the heap of feathers will be of greater height than of an iron block....

1
RAY ·

how does the centre of mass of iron be lower than feathers????

1
Shreyan ·

:)

62
Lokesh Verma ·

I was looking at what philip just said.. and that is what i was taught in class IX (Even though now we know how many of those things are wrong :D)

btw Shreyan what you said also makes a lot of sense :)

And thankfully both of you together have given the complete picture :)

1
Philip Calvert ·

[11] [9] I think everyone is messing up this one so let me try my hand as well :D

"If you were given 1 kg feathers and 1 kg iron..

And I put them on a spring balance.. which one would show a greater reading... ??"

The iron one will show a greater reading because of considerably higher buoyancy of feathers.
in vacuum however both will weigh the same :D

1
Shreyan ·

A kilogram of iron would weigh more because the centre of mass of the given amount of iron would be at a lower height than that of the amount of feathers. Therefore, the lump of iron will experience more attraction force from the earth than the mass of feathers.

62
Lokesh Verma ·

@sankara.. in gravity free space.. weight would be zero? (also the frame of reference should be non accelerating..)

62
Lokesh Verma ·

Arrey no ronald..

It is much simpler...

Let me put this question like this..

If you were given 1 kg feathers and 1 kg iron..

And I put them on a spring balance.. which one would show a greater reading... ??

(I hope this one is better phrased?)

3
msp ·

To be precise weight is not same as mass,as we know.Also for finding the weight of the given two we need to know one thing first that is the place where we measuring these,bcos in a gravity free space all the objects have equal weights,

11
Gone.. ·

i remember this was an old riddle bhaiya..n the ans was that both r same...cud b wrong.

11
Gone.. ·

Copied article ::::

1 kg of feathers vs. 1 kg of bricks

* They weigh the same! It's a trick question.

* This is a trick question: A kilogram is a measurement of weight, so they weigh the same. You would need quite a few more feathers, though!

* Assuming that, obviously, the bricks are on the moon, then the feathers weigh more, due to increased gravitational effects.

* Hello?! 1 kg?! they are asking which one is heavy... They both have the same weight so neither is heavier over the other.

* OK they might weigh the same but I would much prefer a kilo of feathers fall on my head than a kilo of bricks!

* It was put to me this way. Instead of bricks it was gold and instead of kilo it was pounds, and a guy argued that the gold would weigh more because of the troy ounce system. They are both the same. Like wich do you get wetter in? walking in the rain or running in the rain. You are still in the rain da -- He was right, one does weigh more in the troy ounce system, and you do get (70%) wetter walking.

* On the other hand, if you wanted to know which would land first when dropped from equal height, it would be the bricks. why? because of course the feathers would float away from each other and take ages to fall to the ground. the bricks would fall like, well, a ton of bricks

* The kilogram is a measurement of weight not mass. this means that depending on the gravitational pull applied to the kilogram, it can weigh different amounts. A kilo of feathers on earth placed on the moon would weigh much less : about 10 grams. in this case the bricks weigh more. also: both on earth, the bricks would weigh more. because of the air resistance on the feathers whilst weighing them the measurement would be inaccurate.

* Weight is measured in Newtons; kilograms is the amount of mass. It doesn't matter how strong gravity is, mass doesn't change. One kilogram of MASS on Earth WEIGHS about 9.8 Newtons.

* For the record, a Kilogram is a measurement of MASS. a gram is also a measurement of MASS.

* "a kilo of feathers on earth placed on the moon would weigh much less : about 10 grams"

* a kilo of feathers placed on the moon would still be 1 kilo. Not .001 kilos (10 grams). They both weigh the same.

* The question is: What weighs more 1kg of feathers or 1kg or bricks? The question is not: What weighs more on the moon....? What weighs more while falling....? What weighs more while wet....? Thus the answer is the bricks and feathers are equal in weight.

* In response to the person talking about comparing gold and feathers, the feathers would weigh more. Gold is measured in Troy ounces, and a pound in Troy ounces is equivalent to 12 normal ounces.

* Hey you guys! You are all complicating the almost simple answer. The answer is the same. And all it takes is just a simple statement : In this question, we are not talking about the bricks or the feathers but we're focusing more on the amount of weight which is 1kg. Of course a brick is a lot heavier than a feather, but since it is stated that 1 kg of feather and 1 kg of bricks, then they're the same. And yes, the question is not, which weighs more in the moon or what planet, or some gravitational pull whatsoever, the question is so simple.

An ounce of gold weighs more than an ounce of feathers (or bricks). I believe you have to find out the number of "grains" in each type of measurment. There are more grains in an ounce of gold. On the other hand, a pound of frathers weighs more than a pound of gold. In avoirdupis there are 16 oz to the pound and in troy there are 12 oz to the pound. Glad to help.

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