When the load on a wire is slowly increased from 3 to 5 kg, the elongation increases from 0.61 to 1.02 mm. The work done during the extension of wire is
Work done in stretching a wire is given by
W = 12 × stretching force × extension.
Net work done in increasing the length from 0.61 mm to 1.02 mm is
W2−W1
here
W2 is workdone in stretching wire to 1.02 mm at aload of 5 kg
W1 is workdone in stretching wire to 0.61 mm at aload of 3 kg
⇒W2−W1=12×5×9.8×1.02×10−3−12×3×9.8×0.61×10−3=0.016 J