JEE Main Physics question
A ball of mass 2 kg moving with velocity 3 ms⁻¹, collides with a spring of natural length 2 m and force constant 144 N m⁻¹. What will be the length of the compressed spring?
Answer: (B)
Solution
½mv² = ½kx² ⟹ x = v√(m/k) = 3√(2/144) = 3/√72 = 1/(2√2) ≈ 0.35 m. Compressed length = 2 − 0.35 ≈ 1.5 m.