A tensile test was conducted on a mild steel bar. The following data was obtain from the testi. Dia of the steel bar= 3 cmii. Gauge length of the bar = 20cmiii. Load at elastic limit=250kNiiii. Extension at a load of 150 kN= .21mmv. Minimum load =380kNvi. Total extension=30 mmvii. Dia of the rod at the failure =2.25cm. Determine:
(a) the young's modulus
(b) the stress at elastic limit
(c) the % elongation
(d) the % decrease in the area