Question:
A stone is dropped from the top of a building. When it crosses a point $5 \mathrm{~m}$ below the top, another stone starts to fall from a point $25 \mathrm{~m}$ below the top. Both stones reach the bottom of building simultaneously. The height of the building is :
$35 \mathrm{~m}$
$45 \mathrm{~m}$
$50 \mathrm{~m}$
$25 \mathrm{~m}$
Correct Option: , 2
Solution:
Time for particle to meet $=\mathrm{t}^{\prime}=\frac{\mathrm{S}_{\mathrm{rel}}}{\mathrm{S}_{\mathrm{rel}}}=\frac{20}{10}=2 \mathrm{sec}$
Time taken by Ist particle to reach ground $=3 \mathrm{sec}$
$\mathrm{H}=\frac{1}{2} \mathrm{~g}(3)^{2}=45 \mathrm{~m}$
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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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