posted by kate on .
(Q1)A wire of cross- sectional area of 0.00006m2 and length 50cm stretches by 0.2mm under a load of 3000n.Calculate the Young's modulus for the wire (a)80000000000Nm-2(b)125000000000Nm-2(c)25000000000Nm-2(d)5000000000Nm-2 (Q2)a square plate of side 10cm is made of a metal of linear expansivity0.00002/k.As the plate is heated from 30c to 100c.The area of one face of the plate will increase to (a)1056cm2(b)104.2cm2(c)102.8cm2(d)101.4cm2
F/A = E ΔL/L
E= F•L/A• ΔL= 3000•0.5/0.00006•0.2•10⁻³ = 125000000000 N/m²
=0.00002 •0.1•70 =0.00014 m
S₁=(0.10014)²=0.010028 m²=100.28 cm²