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Laws Of Motion

Question
CBSEENPH11020736

A body under the action of a force,straight F with rightwards arrow on top space equals space 6 space bold i with bold hat on top space minus space 8 space bold j with bold hat on top space plus 10 space bold k with hat on top acquires an acceleration of 1 ms-2. The mass of this body must be

  • 2 square root of 10 space kg
  • 20 kg

  • 10 kg

  • 10 square root of 2 space kg

Solution

D.

10 square root of 2 space kg

According to Newton's second law of motion, force = mass x acceleration.
Here, 
straight F with rightwards arrow on top equals space 6 space bold i with bold hat on top space minus 8 space bold j with bold hat on top space plus 10 space bold k with hat on top
vertical line straight F vertical line space equals space square root of 36 plus 64 plus 100 end root

space equals space 10 square root of 2 space straight N
straight a space equals space 1 space ms to the power of negative 2 end exponent
straight m space equals space fraction numerator 10 square root of 2 over denominator 1 end fraction space equals 10 space square root of 2 straight g