Two opposite forces F1 = 120N and F2 = 80N act on an heavy elastic plank of modulus of elasticity y = 2×1011 N/m2 and length L = 1m placed over a smooth horizontal surface. The cross-sectional area of plank is A = 0.5m2 . If the change in the length of plank is x × 10–9m, then find x ?
