F = ke
k = F1e1\;\frac{F_1}{e_1}e1F1
F1_11 = 10N, e1_11 = 0.02m
F2_22 = 40N, e2_22 = ?
F1e1\;\frac{F_1}{e_1}e1F1 = F2e2\;\frac{F_2}{e_2}e2F2
100.02\;\frac{10}{0.02}0.0210 = 40e2\;\frac{40}{e_2}e240
e2_22 = 40×0.0210\;\frac{40 \times 0.02}{10}1040×0.02 = 0.08m
The new length = 1 + 0.08 = 1.08m