SATHEE: Vectors 3 Question 20

Vectors 3 Question 20

20. Which of the following expressions are meaningfull operations?

(1998, 2M)

(a) $\vec{u} \cdot (\vec{v} \times \vec{w})$

(b) $(\vec{u} \cdot \vec{v}) \cdot \vec{w}$

(d) $\vec{u} \times (\vec{v} \cdot \vec{w})$

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Answer:

Correct Answer: 20. (a, c)

Solution:

(a) $\vec{u} \cdot (\vec{v} \times \vec{w})$ is a meaningful operation.

Therefore, (a) is the answer.

(b) $\vec{u} \cdot (\vec{v} \cdot \vec{w})$ is not meaningful, since $\vec{v} \cdot \vec{w}$ is a scalar quantity and for dot product both quantities should be vector.

Therefore, (b) is not the answer.

(c) $(\vec{u} \cdot \vec{v}) \vec{w}$ is meaningful, since it is a simple multiplication of vector and scalar quantity. Therefore, (c) is the answer.

(d) $\vec{u} \times (\vec{v} \cdot \vec{w})$ is not meaningful, since $\vec{v} \cdot \vec{w}$ is a scalar quantity and for cross product, both quantities should be vector.

Therefore, (d) is not the answer.

Vectors 3 Question 20

20. Which of the following expressions are meaningfull operations?

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Vectors 3 Question 20

20. Which of the following expressions are meaningfull operations?

Answer:

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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