Final answer:
The stress of the wire is 12.74 MPa and the strain is 0.006%.
Step-by-step explanation:
To calculate the stress of the wire, we divide the force (40N) by the cross-sectional area of the wire. The diameter of the wire is given as 2mm, so the radius is 1mm or 0.001m. Using the formula for the area of a circle (A = πr^2), the cross-sectional area of the wire is 3.14 x (0.001)^2 = 3.14 x 0.000001 = 0.00000314 m^2. Dividing the force (40N) by the cross-sectional area (0.00000314m^2), we get a stress of 40N / 0.00000314m^2 = 12,738,852.87 N/m^2 or 12.74 MPa (megapascals).
To calculate the strain of the wire, we divide the extension (0.24mm) by the original length of the wire (4m). The strain is given as a percentage, so we multiply by 100. The strain is (0.24 / 4000) * 100 = 0.006%