A force F = i - 5 i ^ - 7 j ^ + 3 k ^ acting on a particle causes a displacement s = 3 i ^ + 2 j ^ + a k in its own direction. If the work done is 14 J, then the value of ‘a’ is

Question

A force F = i - 5 i ^ - 7 j ^ + 3 k ^ acting on a particle causes a displacement s = 3 i ^ + 2 j ^ + a k in its own direction. If the work done is 14 J, then the value of ‘a’ is, 0, 5, 15, 1

MARKS App · Accepted Answer

Given, F = - 5 i ^ - 7 j ^ + 3 k ^ , s = 3 i - 2 j ^ + a k ^ And W = F . s …. (i) Substituting above values in Eq. (i), we get 14 = - 5 i ^ - 7 j ^ + 3 k ^ . 3 i ^ - 2 j ^ + a k ^ ⇒ 14 = - 15 + 14 + 3 a ⇒ a = 15 3 = 5

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