Aliah has a plastic toy that weighs 40g. What else does she need to know in order to calculate the density of this toy?
Well, she needs to know the volume....
Now if the toy floats on water then we know that
And if the toy sinks...
The formula for the density of a substance is
40g is the mass of the toy because it denotes the weight of the object.
The volume of the plastic toy is still needed to calculate the density.