What two forces balance each other to keep a nubula of dust and gas from collapsing?

Linear expansivity is a property specific to a material and hence is constant.

Explanation:

Linear expansivity of the material will be constant irrespective of the shape and size of the material because it is a specific property.

It is a tendency of a material to expand in response to the increase in temperature.

The mathematical expression is given as:

where:

= change in temperature

L= initial length of the specimen

= linear expansivity

=change in length