A force $\overrightarrow F$ = ${4\widehat i + 3\widehat j + 4\widehat k}$ is applied on an intersection point of x = 2 plane and x-axis. The magnitude of torque of this force about a point (2, 3, 4) is ___________. (Round off to the Nearest Integer)
Answer (integer)
20
Solution
$\overrightarrow \tau = \overrightarrow r \times \overrightarrow F$<br><br>$$ = \left[ {(2 - 2)\widehat i + (0 - 3)\widehat j + (0 - 4)\widehat k} \right] \times (4\widehat i + 3\widehat j + 4\widehat k)$$<br><br>$$ = ( - 3\widehat j - 4\widehat k) \times (4\widehat i + 3\widehat j + 4\widehat k)$$<br><br>$= - 16\widehat j + 12\widehat k$<br><br>$|\overrightarrow \tau |\, = 20$ units
About this question
Subject: Physics · Chapter: Rotational Motion · Topic: Centre of Mass
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