A 10 cm3 block of paraffin (a type of wax) weighs 0. 085 N. It is carefully submerged in a container of gasoline. One cm3 of gasoline weighs 0.0069 N.

a. What is the weight of the gasoline displaced by the paraffin?

b. Will the block of paraffin sink or float in the gasoline?

You started out by telling us that the block of paraffin has

10 cm³ of volume. When it's completely submerged, it displaces

10 cm³ of gasoline. Each cm³ of gasoline weighs 0.0069N, so

the whole 10 of them weigh (10 x 0.0069) = 0.069 N.

We notice that the block of paraffin weighs more than the gasoline

that it displaces. So there's no doubt about it ... the paraffin sinks

in gasoline.

If you were to drop it into water instead, it wouldn't sink. Each

cm³ of water weighs 0.0098 N, and 10 of those weigh 0.098N.

In water, the paraffin would settle down only until it displaced

its own weight ... 0.085 N, about 8.7 cm³ of water ... and then

it would float right there, with about 87% of it under water and

the other 13% of it above the surface.