# A balanced lever has two weights on it, the first with mass 7 kg  and the second with mass 29 kg. If the first weight is  3 m from the fulcrum, how far is the second weight from the fulcrum?

May 18, 2018

Second weight is $0.724 m$ or $72.4 c m$ from the fulcrum

#### Explanation:

In a balance lever, moments of the two weights are always equal and opposite (i.e, if one is clockwise other is anticlockwise) to each other. Moment is mass multiplied by its distance from fulcrum.

Here first weight is $7 k g .$ and as ts distance from fulcrum is $3 m$, its moment is $3 \times 7 = 21 m k g .$.

Let the distance of second weight from fulcrum be $d$ $m .$ and as its mass is $29 k g .$ its moment is $29 d$

Hence $29 d = 21$ or $d = \frac{21}{29} = 0.724$ i.e. second weight is $0.724 m$ or $72.4 c m$ from the fulcrum