Calculating Change in Length for a Steel Bridge Span Without Expansion Joints

[dymand68]

Homework Statement

Suppose the 1.3 km main span of steel for the Golden Gate Bridge had no expansion joints. How much longer would it be for an increase in temperature of 20°C?

Homework Equations

change in Length=Length*coefficient linear expansion*change in temp.
=1300*(11*10^-6/20)*20

The Attempt at a Solution

incorrect:
.0143 meters
.2625
.1575
correct answer =.286 meters

 

[PhanthomJay]

Homework Statement

Suppose the 1.3 km main span of steel for the Golden Gate Bridge had no expansion joints. How much longer would it be for an increase in temperature of 20°C?

Homework Equations

change in Length=Length*coefficient linear expansion*change in temp.
=1300*(11*10^-6/20)*20

The Attempt at a Solution

incorrect:
.0143 meters
.2625
.1575
correct answer =.286 meters

your formula is correct, so why did you divide by 20??