The diagram above show s the force-extension curve of a piece of wire. The energy stored when the wire is stretched from E to F is?
-
7.5 x 10-3J
- 2.5 x 10-3J
- 1.5 x 10-2J
- 7.5 x 10-1J
The correct answer is: A
Explanation
The energy store is equal to the work done in stretching the wire from E to F given by the \(\frac{1}{2}\)Fe
where e = 0.10 - 0.50 = 0.05m.
F = 0.2 + 0.1 = 0.3N
= \(\frac{1}{2}\) x (0.2 + 0.1) x (0.10 - 0.50) = 7.5 x 10\(^{-3}\)J