Name: Density of Substances
Uploaded: 2019-07-19
Duration: 6 min 34 s
Description: What is the density of a substance? Density is a very important thing to understand but is a bit tricky. Let’s fully grasp the idea of density from this video.

Question

A wooden cube of side

10 cm

has mass

700 g

. What part of it remains above the water surface while floating vertically on the water surface ?

Accepted Answer

Since, mass of wooden cube is $m = 700 g$ and its side is of $l = 10 cm$ .

Then volume of cube is $V = l^{3} = 10^{3} {cm}^{3}$

Then density of wooden cube is $ρ_{wood} = \frac{m}{V} = \frac{700 g}{10^{3} {cm}^{3}} = 0.7 g {cm}^{- 3}$

Using law of floatation: $\frac{Volume of the submerged cube}{Total volume of cube} = \frac{ρ_{wood}}{ρ_{water}}$

$\Rightarrow V_{submerged} = \frac{0.7 g {cm}^{- 3}}{1 g {cm}^{- 3}} \times 10^{3} {cm}^{3}$

$\Rightarrow \Rightarrow V_{submerged} = 700 {cm}^{3}$

So, the volume of cube above the water will be $1000 {cm}^{3} - 700 {cm}^{3} = 300 {cm}^{3}$

So, the vertical height that is above the water surface is $\frac{300 {cm}^{3}}{10 cm \times 10 cm} = 3 cm$ .

Hence, $3 cm$ of vertical height of the wooden cube is floating on the water surface.

A wooden cube of side $10 cm$ has mass $700 g$ . What part of it remains above the water surface while floating vertically on the water surface ?

Important Questions on Upthrust in Fluids, Archimedes' Principle and Floatation

Learn and Prepare for any exam you want !

A wooden cube of side 10 cm has mass 700 g. What part of it remains above the water surface while floating vertically on the water surface ?

Important Questions on Upthrust in Fluids, Archimedes' Principle and Floatation

Learn and Prepare for any exam you want !

A wooden cube of side $10 cm$ has mass $700 g$ . What part of it remains above the water surface while floating vertically on the water surface ?