3. The composite bar shown is firmly attached to unyielding supports at the ends and is subjected to the axial load P shown.  If the aluminum is stressed to 10,000 psi, find the stress in the steel.
  

a. 1000 psi
b. 2000 psi
c. 5000 psi
d. 10,000 psi
e. 20,000 psi