A spiral spring has a length of 14cm when a force of 4N is hung on it. A force of 6N extends the spring by 4cm. Calculate the unstretched length of the spring
Explanation
Using hookes law
(frac{F_1}{e_1} = frac{F_2}{e_2})
but e(_1) = l(_1) = l(_o)
(frac{F_1}{l_1 – l_o}) = (frac{F_2}{e_2})
(frac{4}{14 – _o}) = (frac{6}{4}); 16 = 6(14 – (_o))
14 = 84 – 6(l_o); 16 – 84 = -6(l_o)
(l_o = frac{-68}{-6}) = 11.33cm