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Work Energy and Power question

2009 · Q160
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Work Energy and Power question

2009 · Q160

NEETPhysicsWork Energy and PowerMCQ+4 / −1
An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?
  1. A
    mv3
  2. B
    12mv2{1 \over 2}m{v^2}21​mv2
  3. C
    12m2v2{1 \over 2}{m^2}{v^2}21​m2v2
  4. D
    12mv3{1 \over 2}m{v^3}21​mv3
View written solutionFree

Correct answer: D

Let m be the mass per unit length, so the rate of mass leaving the hose per sec = mv

Rate of kinetic energy K.E = 12(mv)v2=12mv3{1 \over 2}\left( {mv} \right){v^2} = {1 \over 2}m{v^3}21​(mv)v2=21​mv3

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