Question 198: Centre of Mass and Rotational Motion

Question

A triangular plate is shown. A force $$\overrightarrow F $$ = 4$$\widehat i$$ $$-$$ 3$$\widehat j$$ is applied at point P. The torque at point P with respect to point 'O' and 'Q' are :

Accepted Answer

$$\overrightarrow F  = 4\widehat i - 3\widehat j$$
$${\overrightarrow r _1} = 5\widehat i + 5\sqrt 3 \widehat j$$ & $${\overrightarrow r _2} =  - 5\widehat i + 5\sqrt 3 \widehat j$$
Torque about 'O'
$${\overrightarrow 	au  _O} = {\overrightarrow r _1} 	imes \overrightarrow F  = \left( { - 15 - 20\sqrt 3 } ight)\widehat k = \left( {15 + 20\sqrt 3 } ight)\left( { - \widehat k} ight)$$
Torque about 'Q'
$${\overrightarrow 	au  _Q} = {\overrightarrow r _2} 	imes \overrightarrow F  = \left( { - 15 + 20\sqrt 3 } ight)\widehat k = \left( {15 - 20\sqrt 3 } ight)\left( { - \widehat k} ight)$$

Answer

$$-$$ 15 + 20$$\sqrt 3 $$, 15 + 20$$\sqrt 3 $$

Answer

15 $$-$$ 20$$\sqrt 3 $$, 15 + 20$$\sqrt 3 $$

Answer

15 + 20$$\sqrt 3 $$, 15 $$-$$ 20$$\sqrt 3 $$

Answer

$$-$$ 15 $$-$$ 20$$\sqrt 3 $$, 15 $$-$$ 20$$\sqrt 3 $$

Centre of Mass and Rotational Motion

A triangular plate is shown. A force $\overrightarrow F = 4\widehat i - 3\widehat j$ is applied at point P. The torque at point P with respect to point 'O' and 'Q' are :

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