A steel wire of length 1m and diameter 0.8 mm is kept stretched between two rigid supports. What additional stretching force the wire will experience when its temperature falls by 30K? Linear expansivity of steel `alpha = 12 xx 10^(-6) //k` . Young's modulus of steel `Y = 20 xx 10^(10) N //m^(2)`.

Answer

36.1N

Explanation

`F = Y xx prop xx A xx Delta theta = 20 xx 10^(10) xx 12 xx 10^(-6) xx pi xx ( 0.4 xx 10^(-3))^(2) xx 30 = 36.18N`