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Expansion and contraction
Lower Sec Science · Secondary 2 · Hard · Expansion and contraction
Overhead power lines made of metal sag more on a hot afternoon than on a cool morning. Why does this happen?
Use the idea of expansion of solids when heated.
Use the idea of expansion of solids when heated.
- The metal wires expand and become longer when heated, so they sag more.
- The metal wires contract and become shorter when heated, so they sag more.
- The supporting poles become much shorter when heated, pulling the wires downward.
- The metal wires lose mass when heated, so gravity pulls them down more strongly.
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