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Question Number 21936 by Tinkutara last updated on 07/Oct/17
A heavy iron bar of weight W is having  its one end on the ground and the other  on the shoulder of a man. The rod  makes an angle θ with the horizontal.  What is the weight experienced by the  man?
$$\mathrm{A}\:\mathrm{heavy}\:\mathrm{iron}\:\mathrm{bar}\:\mathrm{of}\:\mathrm{weight}\:{W}\:\mathrm{is}\:\mathrm{having} \\ $$$$\mathrm{its}\:\mathrm{one}\:\mathrm{end}\:\mathrm{on}\:\mathrm{the}\:\mathrm{ground}\:\mathrm{and}\:\mathrm{the}\:\mathrm{other} \\ $$$$\mathrm{on}\:\mathrm{the}\:\mathrm{shoulder}\:\mathrm{of}\:\mathrm{a}\:\mathrm{man}.\:\mathrm{The}\:\mathrm{rod} \\ $$$$\mathrm{makes}\:\mathrm{an}\:\mathrm{angle}\:\theta\:\mathrm{with}\:\mathrm{the}\:\mathrm{horizontal}. \\ $$$$\mathrm{What}\:\mathrm{is}\:\mathrm{the}\:\mathrm{weight}\:\mathrm{experienced}\:\mathrm{by}\:\mathrm{the} \\ $$$$\mathrm{man}? \\ $$
Answered by ajfour last updated on 07/Oct/17
(Wcos θ)(L/2)=FL  ⇒ F=((Wcos θ)/2) .
$$\left({W}\mathrm{cos}\:\theta\right)\left({L}/\mathrm{2}\right)={FL} \\ $$$$\Rightarrow\:{F}=\frac{{W}\mathrm{cos}\:\theta}{\mathrm{2}}\:. \\ $$
Commented by ajfour last updated on 07/Oct/17
what if θ=90° .
$${what}\:{if}\:\theta=\mathrm{90}°\:. \\ $$
Commented by Tinkutara last updated on 07/Oct/17
But answer is given independent of θ.
$$\mathrm{But}\:\mathrm{answer}\:\mathrm{is}\:\mathrm{given}\:\mathrm{independent}\:\mathrm{of}\:\theta. \\ $$
Commented by mrW1 last updated on 07/Oct/17
what if the ground is smooth?
$$\mathrm{what}\:\mathrm{if}\:\mathrm{the}\:\mathrm{ground}\:\mathrm{is}\:\mathrm{smooth}? \\ $$

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