Question

A rectangular prism of volume `84` `cm^3` has a mass of `760` `g`. What is the density of the rectangular prism?

Answer 1

`"Density, "rho` `=` `"Mass"/"Volume"`

Explanation:

`rho` `=` `(760*g)/(84*cm^3)` `~=` `10*g*cm^-3` to a first (very rough) approx.

Doing the calculations this way, i.e. with the units included, is a check on the validity of our calculations.

I wanted an answer with units of density, `g*cm^-3`, the calculation gave me answer with such units.

If I got an answer in `cm^3*g^-1` or something similar this persuades me that I have ballsed up the calculation, i.e. mulitplied when I should have divided or vice versa. This is all too easy to do, and all of us have done it.