The lintel of prestressed reinforced concrete in Figure P12.40 is 1.50 m long. The concrete encloses one steel reinforcing rod with a cross-sectional area of 1.50 cm². The rod joins two strong endplates. The cross-sectional area of the concrete perpendicular to the rod is 50.0 cm². Young’s modulus for the concrete is 30.0 × 10⁹ N/m². After the concrete cures and the original tension T₁ in the rod is released, the concrete is to be under compressive stress 8.00 × 10⁶ N/m². 1.50 m.

(a) By what distance will the rod compress the concrete when the original tension in the rod is released? 

(b) What is the new tension T₂ in the rod?

(c) The rod will then be how much longer than its unstressed length?

(d) When the concrete was poured, the rod should have been stretched by what extension distance from its unstressed length?

(e) Find the required original tension T₁ in the rod.

Figure P12.40 

-1.50 m-