What is the definition of inertia

a tendency to do nothing or to remain unchanged.

Explanation:

For example, if you roll a ball, it will continue rolling unless friction or something else stops it by force.

the property of matter by which it retains its state of rest or its velocity along a straight line so long as it is not acted upon by an external force. an analogous property of a force: electric inertia.

or a tendency to do nothing or to remain unchanged.

r = ρ x length / area  

ρ = r x area / length  

ρ is in ohm-meters  

in basic units, it is m³kg/s³a²  

i think this is it.