A certain vector in the x y -plane has an x -component of 4 m and a y -component of 10 m. It is then rotated in the x y -plane so that its x -component is doubled. Then, its new y -component is (appro

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A certain vector in the x y -plane has an x -component of 4 m and a y -component of 10 m. It is then rotated in the x y -plane so that its x -component is doubled. Then, its new y -component is (approximately)

TestHub · Accepted Answer

Here, A = 4 i + 10 j ∴ ∣ A ∣ = ( 4 ) 2 + ( 10 ) 2 ​ = 16 + 100 ​ = 116 ​ m Now, according to question, A = 8 i + n j So, ∣ A ∣ = ( 8 ) 2 + n 2 ​ ∴ 116 ​ = ( 8 ) 2 + n 2 ​ Squaring on both sides 116 = 64 + n 2 or n 2 = 116 − 64 = 52 or n = 7.2 m

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