# How about this? It's about calculations

By lonely_f16

@lonely_f16 (2147)

Philippines

June 18, 2007 6:34am CST

Find the mass of a piece of gold leaf 2x10^-5 cm thick and 1.0 m^2 in area. The mass density of gold is 1.93 x 10^4 kg times m^2
this symbol
^=raised to the power
thanks

2 responses

@celestemichelle (429)

• United States

18 Jun 07

The phrase "the mass density of gold is 1.93 x 10^4kg times m^2" is confusing.
I assume you're refering to density and not mass.
And the units should be mass divided by volume (kg/m^3) not (kg*m^2) as you have written.
If my assumptions are right the answer Rakhii got is correct.

1 person likes this

@rakhii (1302)

• India

18 Jun 07

Density = Mass/Volume
Mass = Density x Volume
Volume = Area x Height
= 2x 10^-5 cm x 1 m^2
= 2 x 10^-7 m x 1m^2 (1m = 100cm)
= 2 x 10^-7 m^3
Now, mass = 1.93 x 10^4 kg/m^3 x 2 x 10^-7 m^3
Therefore, mass = 3.86 x 10^-3 kg
Mass = 3.86 g (1000g = 1kg)
Note : Density = kg/m^3 not kg/m^2
I hope the answer is correct. You can please recheck.