a$)$ Consider a composite scaffold for repairing large bone defects. The scaffold is composed of $60\%$ hydroxyapatite $($E$=5$ GPa$)$ and $40\%$ polycaprolactone $($E$=300$ MPa$).$ For a cylindrical scaffold of radius $=10$ mm and an axial compressive force $=2000$ N$,$ how much$$force$,$ in units of newtons $($N$),$ is experienced by the polycaprolactone portion of the scaffold?

b$)$ Consider a composite scaffold for repairing large bone defects. The scaffold is composed of $60\%$ hydroxyapatite $($E$=5$ GPa$)$ and $40\%$ polycaprolactone $($E $=300$ MPa$).$ For a cylindrical scaffold of radius $=10$ mm and length $=30$ mm$,$ and an axial compressive force $=2000$ N$,$ what is the change in length, in units of millimeters $($mm$),$ of the scaffold?