Question 447: Centre of Mass and Rotational Motion

Question

The position vector of 1 kg object is $$\overrightarrow r  = \left( {3\widehat i - \widehat j} \right)m$$ and its velocity $$\overrightarrow v  = \left( {3\widehat j + \widehat k} \right)m{s^{ - 1}}$$. The magnitude of its angular momentum is $$\sqrt x $$ Nm where x is ___________.

Accepted Answer

$$\left| {\overrightarrow i } ight| = \left| {\overrightarrow r  	imes (m\overrightarrow v )} ight|$$
$$ = \left| {(3\widehat i - \widehat j) 	imes (3\widehat j + \widehat k)} ight|$$
$$ = \left| { - \widehat i - 3\widehat j + 9\widehat k} ight|$$
$$ = \sqrt {91} $$

Centre of Mass and Rotational Motion

The position vector of 1 kg object is $\overrightarrow r = \left( {3\widehat i - \widehat j} \right)m and its velocity \overrightarrow v = \left( {3\widehat j + \widehat k} \right)m{s^{ - 1}}. The magnitude of its angular momentum is \sqrt x $ Nm where x is ___________.

Integer / Numeric Answer Type