Kinematics Question 144

Question: If a unit vector is represented by $ 0.5\hat{i}+0.8\hat{j}+c\hat{k} $ , then the value of c is [CBSE PMT 1999; EAMCET 1994]

Options:

A) 1

B) $ \sqrt{0.11} $

C) $ \sqrt{0.01} $

D) $ \sqrt{0.39} $

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Answer:

Correct Answer: B

Solution:

Magnitude of unit vector = 1
therefore $ \sqrt{{{(0.5)}^{2}}+{{(0.8)}^{2}}+c^{2}}=1 $

By solving we get $ c=\sqrt{0.11} $



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