question_answer

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 \[20\text{ }m{{s}^{-1}}\]. Neglect the change in the area of cross-section of the cord while stretched. The Young's modulus (in \[N{{m}^{-2}}\]) of rubber is closest to:

Answer:

\[\left( \mathbf{2}.\mathbf{3}\times \mathbf{1}{{\mathbf{0}}^{\mathbf{6}}} \right)\]