A balanced lever has two weights on it, the first with mass $14 kg$ and the second with mass $9 kg$ . If the first weight is $2 m$ from the fulcrum, how far is the second weight from the fulcrum?

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Answer 1 · 2017-03-07T07:16:09

$3.1m$

A moment is the product of force and the distance over which the force acts.

$M = Fd$

In a balanced lever, both moments are equal to each other, so

$M_1 = M_2$

$F_1d_1 = F_2d_2$

We can work out the force either side by $F=ma$ , where $a~~10ms^-2$ , so

$F_1 = 14 xx 10 = 140N$

$F_2 = 9 xx 10 = 90N$

and put these values, along with $d_1 = 2m$ (from the question) into the equation:

$2m xx 140N = d xx 90N$

$d = 280/90 = 3.1m$

A balanced lever has two weights on it, the first with mass 14 kg 14 kg and the second with mass 9 kg9 kg. If the first weight is 2 m 2 m from the fulcrum, how far is the second weight from the fulcrum?