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
-
A.
7.5 x 10-3J -
B.
2.5 x 10-3J -
C.
1.5 x 10-2J -
D.
7.5 x 10-1J
Correct Answer: Option D
Explanation
Energy store is equal to the work done in stretching the wire from E to F given by the area of the shaded trapezium under the graph.
= 1/2(0.1 x 0.2) x (0.1 – 0.05)
= 1/2(0.3) x 0.05
= 0.15 x 0.05
= 0.075
= 7.5 x 10-1J