Question
A force $(\vec F) = 3\hat i + c\hat j + 2\hat k$ acting on a particle causes a displacement: $(\vec s)\, = - 4\hat i + 2\hat j + 3\hat k$ in its own direction. If the work done is $6\,J,$ then the value of $'c'$is
✓
Answer
(c)$W = (3\hat i + c\hat j + 2\hat k).( - 4\hat i + 2\hat j + 3\hat k) = 6\,Joule$
$W = - 12 + 2c + 6 = 6$
$⇒$ $c = 6$
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