JEE Main 20198 AprilMorning Shift
- Exam
- JEE Main
- Year
- 2019
- Date
- 8 April
- Shift
- Morning Shift
- Subject
- Physics
- Chapter
- Mechanical Properties of Solids
JEE Main 2019 · 8 April · Morning Shift · Physics · Mechanical Properties of Solids
A boy’s catapult is made of rubber cord which is 42cm long,...
A boy’s catapult is made of rubber cord which is long, with diameter of cross-section and of negligible mass. The boy keeps a stone weighing on it and stretches the cord by by applying a constant force. When released, the stone flies off with a velocity of . Neglect the change in the area of cross-section of the cord while stretched. The Young’s modulus of rubber is closest to:
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
Elastic potential energy
\left(\pi \times {3}^{2} \times {10}^{- 6} \times 0.42\right)= \left(1.35 \times {10}^{- 6}\right)Y= \dfrac{1}{2}m{v}^{2} = \dfrac{1}{2} \times ( 0.02 \times {\left(20\right)}^{2} )
\left(\pi \times {3}^{2} \times {10}^{- 6} \times 0.42\right)= \left(1.35 \times {10}^{- 6}\right)Y= \dfrac{1}{2}m{v}^{2} = \dfrac{1}{2} \times ( 0.02 \times {\left(20\right)}^{2} )