Question

The position vector of 1 kg object is
\(\stackrel{→}{r} = (3\hat{i} - \hat{j}) m\)
and its velocity
\(\stackrel{→}{v} = (3\hat{j} +\hat{k}) ms^{-1}.\)
The magnitude of its angular momentum is √x Nm where x is

Answer 1

Correct Answer: 91

The correct answer is 91
\(| \stackrel{→}{i} | = | \stackrel{→}{r} × (m\stackrel{→}{v}) |\)
\(= | ( 3\hat{i} - \hat{j} ) × ( 3\hat{j} + \hat{k} ) |\)
\(= | -\hat{i} - 3\hat{j} + 9\hat{k} |\)
\(= \sqrt{91}\)
Therefore The magnitude of its angular momentum is \(\sqrt{x}\) Nm where x is \(\sqrt{91}\)