Question

the area of a square metal is 600mm square.calculate it's New area when it's temperature is raised by 15k ( linear expansivity of metal=1.9*10-5 k-1​

Answer 1

ΔL = L * 1.9E-5 * ΔT

ΔA = A * 2 * 1.9E-5 * ΔT

ΔA = .6 * 3.8E-5 * 1.5E4 mm = .34 mm

New area = 600.34 mm

Note: (L + ΔL)^2 = L + 2 L ΔL + ΔL^2 where ΔL is a small quantity

(L + ΔL)^2 - L^2 = 2 L ΔL = L ΔA

where the coefficient of area expansivity is twice that of linear expansivity