# A balanced lever has two weights on it, the first with mass 7 kg  and the second with mass 4 kg. If the first weight is  3 m from the fulcrum, how far is the second weight from the fulcrum?

Feb 3, 2016

Weight 2 is $5.25 m$ from the fulcrum

#### Explanation:

Moment = Force * Distance

A) Weight 1 has a moment of $21$ ($7 k g \times 3 m$)

Weight 2 must also have a moment of $21$

B) $\frac{21}{4} = 5.25 m$

Strictly speaking the kg should be converted to Newtons in both A and B because Moments are measured in Newton Metres but the gravitational constants will cancel out in B so they were left out for simplicity's sake