JEE Main Physics question
A spring of 40 mm long is stretched by the application of a force. If 10 N force is required to stretch the spring through 1 mm, then the work done in stretching the spring through 40 mm is
Answer: (D)
Solution
k = F/x = 10/(1×10⁻³) = 10⁴ N/m. W = ½kx² = ½(10⁴)(40×10⁻³)² = ½(10⁴)(1.6×10⁻³) = 8 J.