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6.System of Particles and Rotational Motion
easy
The angular velocity of a body is $\mathop \omega \limits^ \to = 2\hat i + 3\hat j + 4\hat k$ and a torque $\mathop \tau \limits^ \to = \hat i + 2\hat j + 3\hat k$ acts on it. The rotational power will be .......... $W$
A
$20$
B
$15$
C
$\sqrt {17} $
D
$\sqrt {14} $
Solution
Power $(P) = \overrightarrow \tau \,.\,\overrightarrow \omega $
$ = \,(i + 2\hat j + 3\hat k)\,.\,(2\hat i + 3\hat j + 4\hat k)$
$ = 2 + 6 + 12$
$= 20\ W$
Standard 11
Physics
