If a =4i ˆ+6j ˆ and b =3j ˆ+4k ˆ, then the vector form of the component of aĀ  along bĀ  is

(a) 18/5 (3i ˆ+4k ˆ )Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā  Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā (b) 18/25 (3j ˆ+4k ˆ )

(c) 18/5 (3i ˆ+4k ˆ )Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā  Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā (d) 18/25(4i ˆ+6j ˆ)

[MCQ] If a = 4i + 6j, b = 3j + 4k, then vector component of a along b - CBSE Class 12 Sample Paper for 2024 Boards

part 2 - Question 12 - CBSE Class 12 Sample Paper for 2024 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12
part 3 - Question 12 - CBSE Class 12 Sample Paper for 2024 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12

Ā 

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Transcript

Now, Vector component of š‘Ž āƒ— along š‘ āƒ— = Projection Ɨ Unit vector of š’ƒ āƒ— = šŸ/("|" š’ƒ āƒ—"|" ) (š‘Ž āƒ—. š‘ āƒ—) Ɨ š‘ āƒ—/(|š‘ āƒ—|) = ((š‘Ž āƒ—". " š‘ āƒ—)/怖\ |š‘ āƒ—|怗^2 ) š‘ āƒ— ) Now, š’‚ āƒ— = 4š‘– ˆ+6š‘— ˆ = šŸ’š’Š ˆ+šŸ”š’‹ ˆ + 0 š’Œ ˆ š’ƒ āƒ— = 3š‘— ˆ+4š‘˜ ˆ = 0š’Š ˆ + šŸ‘š’‹ ˆ+šŸ’š’Œ ˆ Finding š’‚ āƒ—. š’ƒ āƒ— (š’‚ āƒ—. š’ƒ āƒ—) = (4 Ɨ 0) + (6 Ɨ 3) + (0 Ɨ 4) = 0 + 18 + 0 = 18 Magnitude of š‘ āƒ— = √(02+32+42) |š’ƒ āƒ— | = √(0+9+16) = √25 = 5 Now, Vector component of š‘Ž āƒ— along š‘ āƒ— = ((š‘Ž āƒ—". " š‘ āƒ—)/怖\ |š‘ āƒ—|怗^šŸ ) š‘ āƒ— = 18/怖\ 5怗^šŸ (3š‘— ˆ+4š‘˜ ˆ) = šŸšŸ–/šŸšŸ“ (šŸ‘š’‹ ˆ+šŸ’š’Œ ˆ ) So, the correct answer is (b)

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