# A balanced lever has two weights on it, the first with mass 2 kg  and the second with mass 38 kg. If the first weight is  18 m from the fulcrum, how far is the second weight from the fulcrum?

Dec 11, 2015

This problem can be easily solved by "Law of moments" which is just equating net torque on the system to zero.

#### Explanation:

Moment due to the ${m}_{1}$=2kg mass at ${l}_{1}$=18m= ${m}_{1} {l}_{1}$=$2 \setminus \times 18$=$36$
let it be at a distance $x$ from the fulcrum.
Moment due to the ${m}_{2}$=38kg mass at ${l}_{2}$= $x$ distance=$38 x$
Law of moments says-
${m}_{1} {l}_{1} = {m}_{2} {l}_{2}$
$38 x = 36$
$x = \setminus \frac{36}{38} m = \setminus \frac{18}{19} m = 0.94 m$