Question

Piece of plastic has a mass of 6.9 kg and a volume of 722 cm3. What is its density in g/cm3?

Answer 1

Answer:

mass = 6.9 kg = 6900 g

volune= 722 cm3

density= mass/volume

density= 6900/722

= 9.55 g/ cm3

Answer 2

Answer:

$\boxed {\boxed {\sf d \approx 9.56 \ g/cm^3}}$

Explanation:

We want to find the density of the plastic in grams per cubic centimeter.

Density is found by dividing the mass by the volume.

$d=\frac {m}{v}$

We know the mass is 6.9 kilograms and the volume is 722 cubic centimeters We must convert kilograms to grams.

• There are 1000 grams in 1 kilogram.

• $6.9 \ kg *\frac{1000 \ g }{1 \ kg} = 6.9 * 1000 \ g= 6900 \ g$

Now we know the mass and volume. Substitute the values into the density formula.  

$d=\frac{ 6900 \ g }{722 \ cm^3}$

$d= 9.5567867 \ g/cm^3$

Let's round to the nearest hundredth. The 6 in the thousandth place tells us to round the 5 to a 6.

$d \approx 9.56 \ g/cm^3$

The density of the plastic is about 9.56 grams per cubic centimeter