Question:
A uniform heavy rod of weight $10 \mathrm{~kg} \mathrm{~ms}^{-2}$, crosssectional area $100 \mathrm{~cm}^{2}$ and length $20 \mathrm{~cm}$ is hanging from a fixed support. Young modulus of the material of the rod is $2 \times 10^{11} \mathrm{Nm}^{-2}$. Neglecting the lateral contraction, find the elongation of rod due to its own weight.
$2 \times 10^{-9} \mathrm{~m}$
$5 \times 10^{-8} \mathrm{~m}$
$4 \times 10^{-8} \mathrm{~m}$
$5 \times 10^{-10} \mathrm{~m}$
Correct Option: , 4
Solution:
We know,
$\Delta \ell=\frac{\mathrm{WL}}{2 \mathrm{AY}}$
$\Delta \ell=\frac{10 \times 1}{2 \times 5} \times 100 \times 10^{-4} \times 2 \times 10^{11}$
$\Delta \ell=\frac{1}{2} \times 10^{-9}=5 \times 10^{-10} \mathrm{~m}$
Option (4)
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All Study Material
- JEE Main
- Exam Pattern
- Previous Year Papers
- PYQ Chapterwise
- Physics
- Kinematics 1D
- Kinemetics 2D
- Friction
- Work, Power, Energy
- Centre of Mass and Collision
- Rotational Dynamics
- Gravitation
- Calorimetry
- Elasticity
- Thermal Expansion
- Heat Transfer
- Kinetic Theory of Gases
- Thermodynamics
- Simple Harmonic Motion
- Wave on String
- Sound waves
- Fluid Mechanics
- Electrostatics
- Current Electricity
- Capacitor
- Magnetism and Matter
- Electromagnetic Induction
- Atomic Structure
- Dual Nature of Matter
- Nuclear Physics
- Radioactivity
- Semiconductors
- Communication System
- Error in Measurement & instruments
- Alternating Current
- Electromagnetic Waves
- Wave Optics
- X-Rays
- All Subjects
- Physics
- Motion in a Plane
- Law of Motion
- Work, Energy and Power
- Systems of Particles and Rotational Motion
- Gravitation
- Mechanical Properties of Solids
- Mechanical Properties of Fluids
- Thermal Properties of matter
- Thermodynamics
- Kinetic Theory
- Oscillations
- Waves
- Electric Charge and Fields
- Electrostatic Potential and Capacitance
- Current Electricity
- Thermoelectric Effects of Electric Current
- Heating Effects of Electric Current
- Moving Charges and Magnetism
- Magnetism and Matter
- Electromagnetic Induction
- Alternating Current
- Electromagnetic Wave
- Ray Optics and Optical Instruments
- Wave Optics
- Dual Nature of Radiation and Matter
- Atoms
- Nuclei
- Semiconductor Electronics: Materials, Devices and Simple Circuits.
- Chemical Effects of Electric Current,
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