SATHEE: Kinematics Question 153

Kinematics Question 153

Question: The angle between the two vectors $\vec{A} = 3 \hat{i} + 4 \hat{j} + 5 \hat{k}$ and $\vec{B} = 3 \hat{i} + 4 \hat{j} - 5 \hat{k}$ will be [Pb. CET 2001]

Options:

A) $90^{\circ}$

B) $0^{\circ}$

C) $60^{\circ}$

D) $45^{\circ}$

Show Answer

Answer:

Correct Answer: A

Solution:

$\cos θ = \frac{\vec{A} . \vec{B}}{| A | | B |} = \frac{(3 \hat{i} + 4 \hat{j} + 5 \hat{k}) (3 \hat{i} + 4 \hat{j} - 5 \hat{k})}{\sqrt{9 + 16 + 25} \sqrt{9 + 16 + 25}}$

$= \frac{9 + 16 - 25}{50} = 0$
therefore $\cos θ = 0$ ,
$∴$ $θ = 90^{\circ}$

Kinematics Question 153

Question: The angle between the two vectors $\vec{A} = 3 \hat{i} + 4 \hat{j} + 5 \hat{k}$ and $\vec{B} = 3 \hat{i} + 4 \hat{j} - 5 \hat{k}$ will be [Pb. CET 2001]

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

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Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Kinematics Question 153

Question: The angle between the two vectors A→=3i^+4j^+5k^ and B→=3i^+4j^−5k^ will be [Pb. CET 2001]

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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Question: The angle between the two vectors $\vec{A} = 3 \hat{i} + 4 \hat{j} + 5 \hat{k}$ and $\vec{B} = 3 \hat{i} + 4 \hat{j} - 5 \hat{k}$ will be [Pb. CET 2001]