4. A bar of length 1000 mm and diameter 30 mm is centrally bored for 400 mm, the bore diameter being 10 mm as shown below. Under a load of 30 kN, if the extension of the bar is 0.222 mm, what is the modulus of elasticity of the bar? (Ans E = 200736 N/mm?) 30 kN - D = 30 d = 30 30 kN 400 1000-