A boy’s catapult is made of rubber cord which is 42 cm long, with 6 mm diameter of cross-section and of negligible mass. The boy keeps a stone weighing 0.02 kg on it and stretches the cord by 20 cm by applying a constant force. When released, the stone flies off with a velocity of 20 ms–1 . Neglect the change in the area of cross-section of the cord while stretched. The Young’s modulus of rubber is closest to -
(1) 103 Nm–2 (2) 104 Nm–2 (3) 106 Nm–2 (4) 108 Nm–2
