Question

Two children of mass 18 kg and 29 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. If the children are separated by a distance of 5 m, at what distance from the pivot point is the small child sitting in order to maintain the balance?

Answer 1

3.085 [m].

Step-by-step explanation:

1) The rule:

m₁*g*l₁=m₂*g*l₂, where m₁ and l₁ - the mass and distance for the small child, m₂ and l₂ - for the big child;

2) according to the condigion l₁+l₂=5, then

3) it is possible to make up the system:

`\left \{ {{l_1+l_2=5} \atop {m_1*l_1=m_2*l_2}} \right. \ = > \ \left \{ {{l_1=5-l_2} \atop {18*(5-l_2)=29*l_2}} \right. \ = > \ \left \{ {{l_1=(145)/(47)} \atop {l_2=(90)/(47)}} \right.`

4) finally, l₁=145/47≈3.085 [m].