A body of mass 11kg is suspended from a ceiling fan by an aluminum wire of length 2m and diameter 2mm. Calculate the elastic energy stored in the wire [Young’s modulus of aluminum is 7.0 x 1010Nm-2, g = 10ms-2, (pi) = 3.142]`
-
A.
1.1 x 10-1J -
B.
5.5 x 10-2J -
C.
1.1 x 10-4J -
D.
5.5 x 10-8J
Correct Answer: Option B
Explanation
e = (frac{4FI}{Y pi d^2} = frac{4 times 11 times 10 times 2}{7 times 10^3 times 3.14(2 times 10^{-2})^2})
= 0.001m
E = (frac{1}{2} Fe = frac{1}{2} times 110 times 0.001)
= 5.5 x 10-2J