Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET 2015
Exam
NEET
Year
2015
Subject
Physics
Chapter
Work, Power and Energy

NEET 2015 · Physics · Work, Power and Energy

A ball is thrown vertically downwards from a height of 20 m with an...

A ball is thrown vertically downwards from a height of 20m20 m with an initial velocity v0{v}_{0}. It collides with the ground, loses 5050 percent of its energy in collision and rebounds to the same height. The initial velocity v0{v}_{0} is: (Take g=10ms−2g = 10m{s}^{- 2})A ball is thrown vertically downwards from a height of 20 m with an initial velocity v _ 0 . It collides with the

Options

  1. A20ms−120m{s}^{- 1}
  2. B28ms−128m{s}^{- 1}
  3. C10ms−110m{s}^{- 1}
  4. D14ms−114m{s}^{- 1}

Correct answer

A. 20ms−120m{s}^{- 1}

Step-by-step solution

A ball is thrown vertically downwards from a height of 20 m with an initial velocity v _ 0 . It collides with the

kinetic energy of the ball on reaching ground

KE1=mgh+12mv02K{E}_{1} = mgh + \dfrac{1}{2} m{v}_{0}^{2}

after collision KE12=mgh\dfrac{K{E}_{1}}{2} = mgh

mgh+12mv022=mgh\dfrac{mgh + \dfrac{1}{2} m{v}_{0}^{2}}{2} = mgh

v0=2gh=20ms−1{v}_{0} = \sqrt{2gh} = 20\text{m}{\text{s}}^{- 1}
Practice Work, Power and Energy on Quantrex Academy →

More from Work, Power and Energy

All Work, Power and Energy questions Full Work, Power and Energy list All NEET PYQs