011-40705070  or
Select Board & Class
• Select Board
• Select Class
Subject: Science , asked on 27/5/15

# which one is heavier 100 kg cotton or 100kg iron ?

100 kg cotton will be heavier.

This is because...

Upthrust acts on both iron and cotton. Cotton has a lower density than that of iron and therefore the upthrust is more whereas upthrust is less on iron compared to cotton.

Now, we know that UPTHRUST= Actual weight-apparent weight

It is given that apparent weight is 100kg in both the causes.

We know upthrust is more on cotton.

Let us suppose upthrust on cotton is 10N

The,

Upthrust= Actual weight- Apparent weight

10=Actaul weight - 100

110kg=Actual weight of cotton

Even if the upthrust on iron is 9.9 N

Then,

Upthrust= Actual weight - Apparent weight

9.9=Actual weight- 100

109.9=Actual weight

PLEASE NOT THAT WE ARE ASSUMING THE MAGNITUDE OF UPTHRUST! :)

Therefore, Cotton is heavier!

• 7

Cotton is heavier. Surely

• 1
the apparent weight of both of them is the same, but the buoyant force of cotton is high since the volume of cotton is more than iron. Therefore, true weight of cotton is more.
• 1

Of course it is 100kg of iron

• -1

dude both r same!!! both r 100kg!!!

• -2

iron is heavier

• -2
Both weigh the same, 100 kg. So although their densities are different, they will weigh the same.
• -3

both are same because both are of 100 kg each

• -3