A rock has a density of 17 gm/cc. If it is cut into 3 equal pieces, what will be the dencity of each peice?

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- Apr 9th 2008, 02:41 PMsoccerchic96Volume, Density. Mass
A rock has a density of 17 gm/cc. If it is cut into 3 equal pieces, what will be the dencity of each peice?

- Apr 9th 2008, 02:47 PMtopher0805
Uhmm.....

Density is defined as Mass divided by Volume. It's a ratio. So, when the rock is cut into 3, does that ratio change for any of the three pieces? - Apr 9th 2008, 03:09 PMsoccerchic96Need equation
No, the ratio doesn't change, but I don't know how to express it in a formula.

- Apr 9th 2008, 03:15 PMtopher0805
Try this:

$\displaystyle D_1=17$

$\displaystyle D_1=\frac {M}{V}$

So when the rock is cut into three equal pieces, the mass and volume are also cut into three equal pieces:

$\displaystyle D_2=\frac {\frac {M}{3}}{\frac {V}{3}}$

Remember that to divide fractions you flip and multiply. So:

$\displaystyle D_2=\frac {M}{3}\cdot \frac {3}{V}$

$\displaystyle D_2=\frac {M}{V}$

Therefore:

$\displaystyle D_2=D_1$

$\displaystyle D_2=17$