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  1. Chapter 10 Class 12 Vector Algebra
  2. Serial order wise

Transcript

Ex 10.3, 8 Find the magnitude of two vectors ๐‘Ž โƒ— and ๐‘ โƒ—, having the same magnitude and such that the angle between them is 60ยฐ and their scalar product is 1/2 . Given, magnitude of two vectors ๐‘Ž โƒ— and ๐‘ โƒ— is same So, |๐‘Ž โƒ— | = |๐‘ โƒ— | We know that , ๐‘Ž โƒ— . ๐‘ โƒ— = |๐‘Ž โƒ— | |๐‘ โƒ— | cos ฮธ , ฮธ is the angle between ๐‘Ž โƒ— and ๐‘ โƒ— Given ฮธ = 60ยฐ & ๐‘Ž โƒ— . ๐‘ โƒ— = 1/2 Now, ๐‘Ž โƒ— . ๐‘ โƒ— = |๐‘Ž โƒ— | |๐‘ โƒ— | cos ฮธ ๐‘Ž โƒ— . ๐‘ โƒ— = |๐‘Ž โƒ— | |๐‘Ž โƒ— | cos 60ยฐ 1/2 = |๐‘Ž โƒ— |2 ร— 1/2 |๐‘Ž โƒ— |2 = 1 |๐‘Ž โƒ— | = ยฑ 1 Since, magnitude of a vector is not negative, So, |๐‘Ž โƒ— | = 1 So |๐’‚ โƒ— | = |๐’ƒ โƒ— | = 1 Thus, magnitude of ๐‘Ž โƒ— and ๐‘ โƒ— is 1.

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.