Suppose you have a piece of rubber that obeys the Mooney$-$Rivlen

equation:

$=G(-\frac{2}{{}^2})$

The stress required to elongate a piece of rubber by $50\%$ at $20.C$ is

MPa. About how many submolecules $N$ per unit volume $V$ does

the piece of rubber contain?

$\frac{N}{V}=,mo\frac{l}{m^3}$