Answer:
3.84 erg
Explanation:
According to Hooke's law, the energy required to stretch a spring by x length is
[tex]E = kx^2/2[/tex]
where k is the spring constant. We can plug in E = 4 and x = 10 to estimate k
[tex]4 = k10^2/2[/tex]
[tex]4 = 50k[/tex]
[tex]k = 4 / 50 = 0.08[/tex]
To stretch 4cm further (at 14cm), the total work required is
[tex]E_2 = kx_2^2 = 0.08*14^2/2 = 7.84[/tex]
The additional work needed is 7.84 - 4 = 3.84 erg
