An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

Volume

Formula

V = l*w*h

Solution

l=50 cm

w= 40 cm

h = 0.20 cm

V = 50*40*0.2

V = 400 cm^3

Density

D = m/V

D = ???

m = 60 grams

V = 400 cm^3

D = 60 grams / 400 cm^3 = 0.15 grams / cm^3

Kg/m^3

You should do the kg / m^3 by using dimensional analysis.

0.15 grams / cm^3 [ 1 kg / 1000 grams] * [100 cm * 100 cm * 100 cm / 1 m^3]

0.15 grams / cm^3 [ 1 kg / 1000 grams] * [1,000,000 cm^3 / 1 m^3]

0.15  grams /cm^3 [1,000,000 cm^3  / 1000 grams ] [ kg/m^3}

0.15 * 1000 kg/m^3 = 150 kg / m^3

The point of this is that everything else cancels out.

So you have two answers

D = 0.150 grams / cm^3

D = 150 kg /m^3