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:
A. 106 N m-2
B. 104 N m-2
C. 108 Nm-2
D. 103 N m-2
Answer:A
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:
A. 106 N m-2 B. 104 N m-2 C. 108 Nm-2 D. 103 N m-2