Let \(\mathbf{u}\) and \(\mathbf{v}\) be two non-zero vectors. Then the magnitude of the cross product…

Let \(\mathbf{u}\) and \(\mathbf{v}\) be two non-zero vectors. Then the magnitude of the cross product \(\mathbf{u} \times \mathbf{v}\) is always
  1. \( < |u||v|\)
  2. \(=|u||v|\)
  3. \(>|u||v|\)
  4. \(=0\)

Solution

The cross product of \(u\) and \(v\) non-zero vectors is \(\mathbf{u} \times \mathbf{v}=|\mathbf{u} \| \mathbf{v}| \sin \theta \hat{\mathbf{n}}\), if angle between them is \(\theta\). So, \(\quad|u \times v|=|u||v||\sin \theta|\) \(\Rightarrow \quad|u \times v| \leq|u||v| \quad \therefore|\sin \theta| \leq 1\)

Asked in: AP EAMCET 2020 (18 Sep Shift 1)

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