Work Energy And Power Question 199

Question: A force of $ 2\hat{i}+3\hat{j}+4\hat{k}\ N $ acts on a body for 4 second, produces a displacement of $ (3\hat{i}+4\hat{j}+5\hat{k})m. $ The power used is [Pb. PET 2001; CBSE PMT 2001]

Options:

A) 9.5 W

B) 7.5 W

C) 6.5 W

D) 4.5 W

Show Answer

Answer:

Correct Answer: A

Solution:

$ P=\frac{\overrightarrow{F}.\overrightarrow{s}}{t}=\frac{(2\hat{i}+3\hat{j}+4\hat{k}).(3\hat{i}+4\hat{j}+5\hat{k})}{4} $

$ =\frac{38}{4}=9.5\ W $



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