A. A wire of diameter 2.8mm supports a weight W. If the tensile stress in the wire is 2 x 10⁷Nmˉ². Find the value of W )

The weight supported by the wire is 123.15 N

Explanation:

Given;

tensile stress in the wire, τ = 2 x 10⁷ Nm⁻²

diameter of the wire, d = 2.8 mm

radius of the wire, r = 1.4 mm = 1.4 x 10⁻³ m

The area of the wire is calculated as;

The weight supported by the wire is calculated as;

W = F = τ x A

W = (2 x 10⁷ Nm⁻²) X (6.158 x 10⁻⁶ m²)

W = 123.15 N

Therefore, the weight supported by the wire is 123.15 N

the current is 0.6

voltage ÷ resistance = current

so 12 ÷ 20 = 0.6

this could be newton#'s law of cooling. the cooling curve is exponential