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Work Energy and Power question

2000 · Q151
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Work Energy and Power question

2000 · Q151

NEETPhysicsWork Energy and PowerMCQ+4 / −1
If F→=(60i^+15j^−3k^)\overrightarrow F = \left( {60\widehat i + 15\widehat j - 3\widehat k} \right)F=(60i+15j​−3k) N and v→=(2i^−4j^+5k^)\overrightarrow v = \left( {2\widehat i - 4\widehat j + 5\widehat k} \right)v=(2i−4j​+5k) m/s, then instantaneous power is
  1. A
    195 watt
  2. B
    45 watt
  3. C
    75 watt
  4. D
    100 watt.
View written solutionFree

Correct answer: B

P = F→.v→=(60i^+15j^−3k^).(2i^−4j^+5k^)\overrightarrow F .\overrightarrow v = \left( {60\widehat i + 15\widehat j - 3\widehat k} \right).\left( {2\widehat i - 4\widehat j + 5\widehat k} \right)F.v=(60i+15j​−3k).(2i−4j​+5k)

= 120 – 60 – 15 = 45 watts.

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