A rubber ball is released from a height of $5 \mathrm{~m}$ above the floor. It bounces back repeatedly, always rising to $\frac{81}{100}$ of the height through which it falls. Find the average speed of the ball. (Take $\mathrm{g}=10 \mathrm{~ms}^{-2}$ )
$3.0 \mathrm{~ms}^{-1}$
$3.50 \mathrm{~ms}^{-1}$
$2.0 \mathrm{~ms}^{-1}$
$2.50 \mathrm{~ms}^{-1}$
Correct Option: , 4
(4) $v_{0}=\sqrt{2 g h}$
$\mathrm{v}=\mathrm{e} \sqrt{2 \mathrm{gh}}=\sqrt{2 \mathrm{gh}}$
$\Rightarrow \mathrm{e}=0.9$
$S=h+2 e^{2} h+2 e^{4} h+\ldots \ldots \ldots$
$\mathrm{t}=\sqrt{\frac{2 \mathrm{~h}}{\mathrm{~g}}}+2 \mathrm{e} \sqrt{\frac{2 \mathrm{~h}}{\mathrm{~g}}}+2 \mathrm{e}^{2} \sqrt{\frac{2 \mathrm{~h}}{\mathrm{~g}}}+\ldots \ldots \ldots$
$\mathrm{v}_{\mathrm{av}}=\frac{\mathrm{s}}{\mathrm{t}}=2.5 \mathrm{~m} / \mathrm{s}$
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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,