A tube of aluminium of 40 mm external diameter and 20 mm internal diameter is snugly fitted on a solid steel rod of 20 mm diameter. The composite bar is subjected to an axial compressive force P. If the stress on steel bar is 70 N/mm2, the stress in the aluminium tube and corresponding value of P will be: (E for steel: 2 × 105 N/mm2 and E for aluminium 7 × 104 N/mm2)

A tube of aluminium of 40 mm external diameter and 20 mm internal diam

1.	A tube of aluminium of 40 mm external diameter and 20 mm internal diameter is snugly fitted on a solid steel rod of 20 mm diameter. The composite bar is subjected to an axial compressive force P. If the stress on steel bar is 70 N/mm2, the stress in the aluminium tube and corresponding value of P will be: (E for steel: 2 × 105 N/mm2 and E for aluminium 7 × 104 N/mm2)
A.	24.5 N/mm2, 45.08 kN
B.	36.5 N/mm2, 60.10 kN
C.	54.5 N/mm2, 73.10 kN
D.	73.80 N/mm2, 92.60 kN
Answer» B. 36.5 N/mm2, 60.10 kN