One end of an elastic string of natural length ‘l’ and modulus ‘X’ is kept fixed while to the other end is attached a particle of mass m which is hanging freely under gravity. The particle is pulled down vertically through a distance ‘x’, held at rest and then released.The motion is

• A. A rectilinear motion with constant speed
• B. A damped oscillatory motion
• C. None of these
• D. A simple harmonic motion

Answer: (D)