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MHT CET · Physics · Work Power Energy

A force \((5 \hat{\imath}-2 \hat{\jmath}+3 \hat{k}) \mathrm{N}\) acts on a body of mass \(2 \mathrm{~kg}\) and displaces it from \((3 \hat{\imath}+2 \hat{\jmath}-\hat{k})$$\mathrm{m}\) to \((6 \hat{\imath}-\hat{\jmath}+4 \hat{k}) \mathrm{m} .\) The work done is

  1. A 27 J
  2. B 18 J
  3. C \(36 \mathrm{~J}\)
  4. D \(9 \mathrm{~J}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(36 \mathrm{~J}\)

Step-by-step Solution

Detailed explanation

\( \vec{d} = \vec{r_2} - \vec{r_1} = (6 \hat{\imath}-\hat{\jmath}+4 \hat{k}) - (3 \hat{\imath}+2 \hat{\jmath}-\hat{k}) = (3 \hat{\imath}-3 \hat{\jmath}+5 \hat{k}) \mathrm{m} \) \( W = \vec{F} \cdot \vec{d} = (5 \hat{\imath}-2 \hat{\jmath}+3 \hat{k}) \cdot (3 \hat{\imath}-3 \hat{\jmath}+5 \hat{k}) \)