posted by Afrah .
A metal rod has a length of 4m at 50 degrees celcius and a length of 6m at 200 degrees celcius. What is it's length at 20 degrees celcius?
Assume that expansion is linear with temperature change. Actually, this is often not the case. The thermal expansion mentioned is also much too high for metals. The thermal coefficient of expansion often varies a lot with temperature.
If a 150 deg C temp rise causes a 50% change in length, a 30 degree drop in temp will cause about a (1/5)*50% or 10% decrease in length. The new length will be 90 cm