A balanced lever has two weights on it, one with mass $4 kg$ and one with mass $8 kg$ . If the first weight is $9 m$ from the fulcrum, how far is the second weight from the fulcrum?

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Answer 1 · 2016-03-24T13:26:08

$4.5m$

From the second condition for static equilibrium, the resultant torque (moments) must be zero, ie $sumvectau=0$ , where $vectau=vecrxxvecF$ .

$therefore r_1F_1-r_2F_2=0$ , where $F=W=mg$ .

$therefore (9xx4g)-(r_2xx8g)=0$

$thereforer_2=36/8=4.5m$ .

A balanced lever has two weights on it, one with mass 4 kg4 kg and one with mass 8 kg8 kg. If the first weight is 9 m 9 m from the fulcrum, how far is the second weight from the fulcrum?