When a man increases his speed by $2\;{\rm{m}}{{\rm{s}}^{ - 1}}$, he finds that his kinetic energy is doubled, the original speed of the man is

$2\left( {\sqrt 2 + 1} \right){\rm{\;m}}{{\rm{s}}^{ - 1}}$

$2\left( {\sqrt 2 - 1} \right){\rm{\;m}}{{\rm{s}}^{ - 1}}$

$4.5{\rm{\;m}}{{\rm{s}}^{ - 1}}$

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JEE PHYSICS MCQ: WORK-ENERGY-POWER

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When a man increases his speed by

2\;\mathrm{m}{\mathrm{s}^{ - 1}}

, he finds that his kinetic energy is doubled, the original speed of the man is

View answer and explanation

Correct option: B

2\left( {\sqrt 2 + 1} \right)\mathrm{\;m}{\mathrm{s}^{ - 1}}

Option B (

2\left( {\sqrt 2 + 1} \right)\mathrm{\;m}{\mathrm{s}^{ - 1}}

) is correct because it solves for the original speed using the relationship between kinetic energy and velocity, given that the kinetic energy doubles when the speed increases by 2 m/s.

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