Rotational Motion

JEE Main level, single correct, medium

108 of 280

Question 108 of 280

A heavy iron bar, of weight WW is having its one end on the ground and the other on the shoulder of a person. The bar makes an angle θ\theta with the horizontal. The weight experienced by the person is :

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Answer: (B) W2\frac{W}{2}


R=R= net reaction force by shoulder
Balancing torque about pt of contact on ground:

W(L2cos⁡θ)=R(Lcos⁡θ)⇒R=W2\begin{aligned} & \mathrm{W}\left(\frac{\mathrm{L}}{2} \cos \theta\right)=\mathrm{R}(\mathrm{L} \cos \theta) \\ & \Rightarrow \mathrm{R}=\frac{\mathrm{W}}{2}\end{aligned}

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