JEE MainPhysicsRotational MotionNumerical+4 / −1
A force N acts at a point m. Then the magnitude of torque about the point m will be N m. The value of x is .
Numerical answer
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Correct answer: 195
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Given data
Force:
Point of application of force:
Point about which torque is to be calculated:
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Position vector from torque point to point of application
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Torque formula
Torque about the given point is
So,
\begin{vmatrix} \hat i & \hat j & \hat k \\ 3 & 1 & -2 \\ 1 & 2 & 3 \end{vmatrix}$$ -
Evaluate the cross product
- \hat j\big(3\cdot 3 - (-2)\cdot 1\big) + \hat k\big(3\cdot 2 - 1\cdot 1\big)$$ $$\vec \tau = \hat i(3+4) - \hat j(9+2) + \hat k(6-1)$$ $$\vec \tau = 7\hat i - 11\hat j + 5\hat k$$ -
Magnitude of torque
Comparing with ,
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Comparison with stored answer
Stored correct answer =
Our derived answer also is .
Final Answer:
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