Question

A piece of coal has a mass of 40 g and volume of 30 cubic centimetre. Find its relative density.

Answer 1

Answer:

To find mass from density, you need the equation Density= Mass ÷ Volume or D= M÷V. The proper SI units for density are g/cubic cm (grams per cubic centimeters), alternately expressed as kg/cubic m (kilograms per cubic meters).

Answer 2

Answer:

Relative density of coal = 4/3

Explanation:

We know that,

Density = Mass/Volume

and

Relative density = Density of substance / Density of water

Given that,

Mass = 40g

Volume = 30cm³

Density of water = 1 g/cm³

Hence,

Density = Mass / Volume

Density = 40/30

Density = 4/3 g/cm³

Hence,

Relative density of coal = Density of coal / Density of water

Relative density of coal = ( 4/3 ) / (1)

Relative density of coal = 4/3