A block attached to a spring, pulled by a constant horizontal force, is kept on a smooth surface as shown in figure. Initially, the spring is in the natural length state. The maximum positive work that the applied force F can do is (given that string does not break) :
Answer & explanation
Correct answer: option 2
Applying Work-Energy Theorem :
\(Fl - \frac{1}{2}kl^2 = 0\)
\(l = \frac{2F}{k}\)
Work done : \(Fl = \frac{2F^2}{k}\)