E-11

It is very important to make firm contact beween the specimen and the strain gauge.

Answer to the question:
2. This is an example of systematic error.
The tape has expanded so the reading is too short. The correct reading can be obtained by
L = Reading (1+a DT) = 20.15 m ( 1 + 12 x 10^-6C^-1 x 10°C) = 20.152 m.