A vector A → is rotated by a small angle ∆ θ radians ∆ θ ≪ 1 to get a new vector B → . In that case B → - A → is :

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B → = A → B → - A → = A → 2 + A → 2 + 2 A → A → cos 180 ° - ∆ θ = A → 2 + A → 2 - 2 A → 2 cos ∆ θ = 2 A → 2 - 2 A → 2 cos ∆ θ = 2 A → 2 1 - cos ∆ θ ∵ 1 - cos ∆ θ = 2 sin 2 ∆ θ 2 = 2 A → 2 × 2 sin 2 ∆ θ 2 = 2 A → sin ∆ θ 2 For small ∆ θ , sin ∆ θ 2 ≃ ∆ θ 2 B → - A → = 2 A → ∆ θ 2 = A → ∆ θ

Physics - Vectors Question with Solution | TestHub

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