# Math Help - another volume hw ?

1. ## another volume hw ?

A student finds a figurine that looks like silver. He wants to find out if the figurine is pure silver. Density of silver is 10.5g/cm cubed. The figurine weighs 300g. He drops the figurine into a graduated cylinder of radius 4cm. The water level rose 1.5cm. Is the figurine pure silver, justify your answer. Is the material of the figurine heavier or lighter per cm than silver.
Hint: Volume of water displaced is equal to the volume of the object submersed.

2. Hello, igottaquestion!

You should be able to reason it out . . .

A student finds a figurine that looks like silver.
He wants to find out if the figurine is pure silver.
Density of silver is 10.5g/cm³. .The figurine weighs 300g.
The water level rose 1.5cm.
Is the material of the figurine heavier or lighter per cm³ than pure silver.
Hint: Volume of water displaced is equal to the volume of the object submerged.

The volume of a cylinder is: . $V \:=\:\pi r^2h$

The figurine displaced a cylinder of water: radius 4 cm, height 1.5 cm.
The volume of the figurine is: . $\pi(4^2)(1.5) \,=\,24\pi\text{ cm}^3$

Its density is: . $\frac{300\text{ gm} }{24\pi\text{ cm}^3 } \;\approx\; 4\text{ gm/cm}^3$

It is much lighter than pure silver.