a 150 m steel bridge has an expansion joint of 12.0 cm at one end at -20.0 deg C.?

Question

at what temp. would the joint be closed?

Answer 1

We have to know the coefficient of expansion.

Answer 2

Coefficient of thermal expansion for steel is 12x10^-6/°C. So for every cm of length, 1°C in temperature change will produce 12E-6 cm of movement.

You only need one equation:
dL=L*a*dT

Where L=length, dL=change in length, a=coeff of therm. exp, dT=change in temperature.

You have a 150m long bridge and you want to grow it .012m. You do your work.

I get -13.4°C

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