Last updated at Dec. 8, 2016 by Teachoo
Ex 10.3, 8 Find the magnitude of two vectors 𝑎 and 𝑏, having the same magnitude and such that the angle between them is 60° and their scalar product is 12 . Given, magnitude of two vectors 𝑎 and 𝑏 is same So, 𝑎 = 𝑏 We know that , 𝑎 . 𝑏 = 𝑎 𝑏 cos θ , θ is the angle between 𝑎 and 𝑏 Given θ = 60° & 𝑎 . 𝑏 = 12 Now, 𝑎 . 𝑏 = 𝑎 𝑏 cos θ 𝑎 . 𝑏 = 𝑎 𝑎 cos 60° 12 = 𝑎2 × 12 𝑎2 = 1 𝑎 = ± 1 Since, magnitude of a vector is not negative, So, 𝑎 = 1 So 𝒂 = 𝒃 = 1 Thus, magnitude of 𝑎 and 𝑏 is 1.
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